Without being able to put anything on the walls it is a tough call for adding more wall color. Perhaps a folding screen which you could hang some paintings or photos on. A tall bookcase too. Valences could be inserted behind the blind tops. Tall candle sticks and floor lamps.

I really like your clean lines and furniture. For now, with this being a new apt., everything looks great to me. The ole' less is more comes to mind.

Liz,
I recently repainted my townhouse with Ellen Kennon's paint colors. I was skeptical of the hype until I saw them in place. They're beautiful! So... I was wondering how her "Ruby" red "Magical Gem" color would look on the wall in the bathroom where the vanity faces, and then adding a bright red-themed shower curtain to counter-balance the wall. I'll bet your bathroom would be gorgeous!

I'm guessing that since the OP is in an apartment and is concerned about putting holes in the walls that painting is out.
It seems that what is needed is more things with height. Someone mentioned a folding screen, which would be good. Tall plants and/or plants on stands would add height, color and texture too.

Liz, I like your esthetic very much. It's clean and liveable, and very serene. In a small space you were clever to pick a palette and stick with it in every room, as that visually expands your space.

A word about landlords and nail holes: if you get very lightweight things to hang, you will only have to use one nail, and that is EASILY filled in invisibly with spackle available premixed in a small container from Home Depot, Wal-Mart, etc. With clean hands must put a bit on your finger, swipe it across the hole and it disappears.

Having said that, I think what your apartment needs is not more furniture, but art! I would follow your already expressed red/white/black theme and your continuum esthetic by purchasing inexpensive prints/ posters all in red, black and white, and framing them all exactly alike with narrow black frames from Target.

Allposters.com has a great variety of inexpensive things that would work beautifully in your space. I looked through a few and here are some in various categories for you to just look at and imagine on your walls. If you're interested in movies, you could probably do it all in that genre (and then reuse them someday in a home media room). If you are interested in schools, art prints, pop or modern art, travel, music---there are many choices in each category that would work well on your walls.

Hanging things in just a few carefully-chosen colours, framed alike, will give a gallery-type of presence to these.

http://www.allposters.com/-sp/Pulp-Fiction-Posters_i1849047_.htm

http://www.allposters.com/-sp/Moulin-Rouge-Posters_i306935_.htm

http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=988301&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=101&f=c&FindID=101&P=4&PP=238&sortby=PD&cname=Movie&SearchID=

http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=2055077&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=101&f=c&FindID=101&P=4&PP=238&sortby=PD&cname=Movie&SearchID=

http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=2549063&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=101&f=c&FindID=101&P=5&PP=238&sortby=PD&cname=Movie&SearchID=

http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=936751&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=101&f=c&FindID=101&P=6&PP=238&sortby=PD&cname=Movie&SearchID=

and for music:
http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=391107&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=122&f=c&FindID=122&P=3&PP=191&sortby=PD&cname=Music&SearchID=

http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=1687770&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=122&f=c&FindID=122&P=5&PP=191&sortby=PD&cname=Music&SearchID=

general interest:
http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=2035468&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=2152&f=c&FindID=2152&P=1&PP=947&sortby=PD&cname=Vintage+Art&SearchID=

http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=997538&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=2152&f=c&FindID=2152&P=2&PP=947&sortby=PD&cname=Vintage+Art&SearchID=

for your kitchen?
http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=826557&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=2152&f=c&FindID=2152&P=2&PP=947&sortby=PD&cname=Vintage+Art&SearchID=

I've always liked this Warhol:
http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=2359405&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=1013&f=c&FindID=1013&P=2&PP=2326&sortby=PD&cname=Fine+Art&SearchID=

and another iconic Warhol:
http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=366915&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=1013&f=c&FindID=1013&P=4&PP=2326&sortby=PD&cname=Fine+Art&SearchID=

a fabulous Keith Haring:
http://www.allposters.com/gallery.asp?startat=/getposter.asp&APNum=1664506&CID=3BB665B701334708BE6C4CE1928C3B22&PPID=1&search=1013&f=c&FindID=1013&P=9&PP=2326&sortby=PD&cname=Fine+Art&SearchID=

To liven things up a bit more, I'd add one more color to the rooms: Yellow (in accessories or whatevers)

My first inclination as well was the need for vertical height.

I would toss a tall fica tree behind that TV in that corner of your LR. I could also see the same thing in your bedroom behind your nightstand. And maybe some bamboo on your bathroom countertop?

If you don't like the fica tree idea, at least try to find a vertical shape to fill those corners and bring the eye up---maybe an open black iron shape of some sort.

I like your spaces, btw. Very clean and fresh.

I like all the above ideas, especially adding a few folding screens/room dividers that will allow you to introduce more colors and/or hang pictures on. I also like the idea of adding one more color, as Teedup mentioned~ yellow.
I'd buy a large, nicely framed print and prop it on your mantel, too. Adding a potted tree is also a great idea. Your apartment is lovely and I'm sure your inlaws will appreciate it . . . especially if you have a comfy guest room set up for them.

Your apartment reminded me a bit of mine. DH and I were apartment dwellers the first 5-years of marriage and we were on an extreme budget. This one-bedroom was very dinky so it was important to not blockade any views, yet I was trying to provide vertical height and separate the "living space" from the "dining space", LOL! I made that little "drape" in between and screwed little cup holder hooks into the ceiling to hang it by. It was easy to patch up after we moved.

But I wanted to encourage you to get creative! Your space is way more chic than mine! ;)

Your window casings are so deep that it would be really easy to mount tension rods and hang drapes within the window frame areas.

Also the Hercules Hooks work really well in dry wall:

Here is a link that might be useful: Hercules Hooks

How about 3M command hooks that doesn't make holes in the walls like the above ones.

Then incorporate some of the other suggestions as well.

Here is a link that might be useful: 3M Command Hooks

You definitely need some curtains or valances to soften things up. Do you like toile? A black and white toile valance in the bath would be very pretty.

Texas,

I love your apartment! What did you hang the pictures from? A curtain rod?

We actually just moved from a very small one-bedroom apartment into a two-bedroom apartment. I don't know if you've encountered this, but everyone always asks us when we're going to buy a house now that we're married. While I'd love to buy, it just doesn't make sense for us right now, and I like the option of having the maintenance man fix up any of my mistakes for me.

As for the decor, I think I solved the bathroom problem at least. I changed the white shower curtain to a black one and added hand towels to the back of the toilet.

The bedroom, however, is still an issue. I grabbed a small shelf from the living room and placed it there to add some vertical space. We're thinking about adding a wall quote (JoAnn Fabrics has some decals for $20). My husband likes the idea of hanging fabric, but I have no idea how we'd go about that.

We tried to pick up an artificial ficas tree from the craft store yesterday, but it wouldn't fit in our car, so that option is out. We also don't trust our cats not to attack it or attempt to climb it.

Don't forget those command strip thingies...I use them because it's a challenge to get nails into my plaster walls at a useful angle!

I love them, plus repositioning is no problem.

You definitely need art on your walls - either use the 3m strips or just patch the nail holes (very, very easy) when you move out. You will be SO glad you did as it will make your house a home.

Great job so far but IMHO without wall art or paint you'll never get to a warm place that feels like home. Don't discount the emotion you have when you walk into your apt. - either you feel it or you feel the lack of it. I think it will feel unfinished until you use your walls. Bite the bullet and create nail holes OR pay the penalty...

Your apartment does look nice, but looks minimalist which is really not my style, so if you're going for the minimalist look, just ignore my comments!

In my MUCH younger days, I lived in a few apartments, as did my husband in his much younger days. We both hung a lot of art on the walls then patched before we moved. It's a no-brainer to patch the tiny nail holes -- no tools needed. You can even use white toothpaste if you don't want to take the time to find spackling compound or drywall mud.

Hanging artwork would make a huge improvement, IMO. I'd also love to see window treatments, but it sounds like that might be too much of a repair for you when you move (although that, too, would be a very easy fix).

(Very cute apartment, Texashottie!!)

Liz, I like your new bathroom look!

I totally understand about the cat problem. Whenever we would put up our Christmas tree in our apartment, our fatty would topple it.

Btw, you need to get a can of bungee cords to keep in the trunk of your car! You would be amazed what special finds you can haul home with just a few bungees---I am the ultimate Bungee Queen. ;)

I found a better pic of my little drape---Liz, it was so easy to sew! I just rolled the edges over and sewed hapharzadly so it wouldn't unravel. The bottom puddles, so there was no issue of sewing a straight line.

And, yes, I did have a curtain rod on the wall. I hung pictures from it regularly, and also hung greenery in it.

I was also thinking for your bedroom... to get some of that vertical height. What about a sultry mosquito net? I think they are so romantic/inviting to a bedroom. You hang it from the ceiling over your pillows and toss the "veil" back over the headboard. It's see-through, thereby not cluttering your space, and I think your DH would like it. All for $19.99! (See my link)

Here is a link that might be useful: Mosquito Net

I can help with your bedroom. I think you need two large pillows behind your striped pillows. I would get a pretty floral fabric with red and black tones or a print. Do you have a fabric store nearby? You might find some already made up that you like. Also, you can find inexpensive woven throws now at places like BB&B, Target etc. I would find one with several of your colors woven in, or just a solid black would look nice gently thrown on the end of your bed. You need a picture on the long wall next to your bed. Also for window covering , I think sheer white pull back curtains on rings would be pretty.

Perhaps one of those black-painted floor screens that hold photos would help to clear off your mantel -- and still display your photos? A floor screen would also add visual height where placed too ......

Then you could lean a mirror against the wall above the mantel --- or at least add a couple of matching black/white vases to each end of the mantel -- with some of your red gerbera daisies.

A few more lamps would work wonders too! Perhaps a lamp on the table by the bed? And a tall thin one would work well in the corner of the bathroom counter too.

And basic white or black wall shelving units from Target would hold books, china, pottery and glass items.

Your LR already looks good so you don't need to worry about the impending visit from in-laws.

I think your LR could benefit from a bright print or painting resting on the mantel. You shouldn't rush into such a purchase tho so unless there is something you have seen that you like you might want to take some time to get this.

Perhaps a red flowering plant or a few bunches of flowers will help give the welcoming look you want.