We need pictures of the whole area and a floor plan. Also, do you have furniture to put in the space? What is your style? TV is always a focal point. How about a fireplace?

From what I can see, you have a lot of natural light potential with the windows but if the neighbor's back yard is your view, you need both privacy and light control.

Agree with those that suggest you draw, to scale, at least this room and adjoining spaces showing all windows and doors (fixed features) on graph paper and post that (preferably along with more pictures of the space).

Is this space part of a "great room" with the kitchen also being a part of the open floor plan?

If the kitchen is part of the open floor plan, is there a peninsula or island between kitchen and dining?

Is the dining room end of this living/dining room more narrow than the living room end?

If the trees on the wall are being left behind by the current owner, hold onto them -- I like them but they are not particularly well placed on that large wall.

Pay attention to any limitations as to where you can put the tv such as a cable box or antenna access. You might consider a portable tv stand, especially if there is any chance there will be a glare from natural light from the windows and/or furniture placement has not yet been decided. A portable tv stand gives you more options as to furniture placement, important in a limited space.

https://www.wayfair.com/Wade-Logan%C2%AE--Caulkins-TV-Stand-for-TVs-up-to-55-X115973500-L6-K~W004862499.html?refid=GX496871586189-W004862499&device=c&ptid=1198921003886&network=g&targetid=pla-1198921003886&channel=GooglePLA&ireid=141191053&fdid=1817&gclid=EAIaIQobChMIvNG1lI_r8QIVkqjICh2FoQP4EAQYASABEgKSuvD_BwE 

A "natural" focal point is most often architectural—fireplace, picture window/french doors, vaulted ceiling—that catches your attention. A wall with paneling, wallpaper or a contrasting paint color is a focal point. A grouping of photos, artwork, a bold rug, even the TV can be a focal point. A room doesn't need to have just one; however, more that three focal points can be visual clutter.

Your room's natural focal point is the picture window. You could further define the focal point with a tree or plant that fills the space like THIS. Regardless of whether there is an obvious focal point, I like to repeat color across the room. Do you have favorite artwork? Try to find drapes, throw pillows and a rug that repeats the main color(s). Is there a prominent color in a room visible from this one? Repeat that color in this room. Here is a Houzz Article on this subject.

While furniture is often placed to focus on a focal point, it doesn't have to be. It makes no sense to face all the furniture towards the picture window if you are also putting a TV in the room. For comfort's sake you set furniture so the TV is easily viewed while sitting.

The focal “wall” in this space is the far wall under the peak ceiling. So if you are using this room for TV watching, then the TV goes on that wall and possibly a bookcase either side. Then sofa facing TV. We need measurements to provide layouts and furniture sizes to help you further. High ceilings often deceive people into thinking they have more floor space than they do. So measurements are vital to prevent costly mistakes.

How many people do you want to seat everyday? Would you describe their size as small in stature, medium or large?

If you don't plan for TV, the green space view may be your actual focal point.

Decided tv will go in this space (50" or 55") as we are unable to put a fireplace on the wall (it abuts a bedroom). Should the bookcases go all the way across the wall or just flank? Decor will be transitional with woodtones, shades of blue-greens and grays with a leather sofa (84"). LR is open to dining and eventually kitchen (with a peninsula when wall comes down as noted in my first post). I am working on a scale drawing right now to figure out placement of furniture. Thanks for all your insights.

With traditional styling you could do wood bookcases either side of TV. IF you have sofa, measure from floor to seat height. Placing the TV at a proper height will be important. You will need a console for under TV to hold cable boxes etc. Plus, it will give nice look and provide storage for TV items you may have. Average TV height from 19” high sofa seat is between 53-56” from floor to CENTER of TV. BUT we can figure that out after you are moved in. I like to get a total vision for a space then I can add elements as budget allows.