Been meaning to post something about this forever! Ez even bugged me last month about it. =) Here are some of my tips for improving your plant photography. I've included some extra photos for examples.

Overall Plant Photos:

Try to include a full shot of the plant. I like to include part of the soil mix or pot to help give some scale to the image. Show off that beautiful form!

Close Details:

My favourite parts of succulents are often the details. Quality close-ups or macros are essential for showing specific problems or the beauty of flowers, leaves, and branches.

A combination of overall photos and closeups is best, such as for this Gasteria.

Higher and Lower Angles:

It's worthwhile trying both high and low angles when taking plant photos. In the photo below, a higher angle favours the symmetry of the flower, while the lower angle helps show off the shape/form of this Aloinopsis.

Side and Back Lighting:

If you're looking to create more dramatic or dynamic images, the light direction is extremely important. When lighting my plants, I prefer to use side light and back lighting whenever possible.

This kind of light helps bring out the texture of the plant and gives depth to the image. Front lighting is typically very flat and less flattering (in general, not all cases).

In the photo below (top), this Lapidaria was lit from several directions. Primarily the rear left which is casting the darker shadow on the soil surface. However, there is added light from above to fill in the shadow and bring out the flower's structures.

In the second photo below (bottom), the 'Gollum' was lit mostly from the right side to emphasize the shape of the plant and strange texture/shapes of the leaves.

Light Sources:

The most obvious is the sun! I love shooting my plants outside on my rooftop in the late afternoon or mid morning. The light is less harsh and the quality of light is very good.

I find best spots are typically at the edge of shady areas (right up to the line between bright light/shade). Don't forget about the direction of the light too. I like to set my plants down in their photo spots and rotate them a little for the best angles.

This Anacampseros was taken in natural light on my rooftop, early afternoon, and in a bright but shady spot.

On the flip side, most of the photos I'm posting around the forums are lit with a 5 flash setup. This gives me a lot of control over how exactly the light is illuminating my plants.

The number of lights isn't really important, just that getting them off your camera adds flexibility and will enable you to be more creative in your lighting setups. Bouncing flashes off white walls/ceilings or using other light modifiers can be quite helpful as well.

The Lithops below (top) was taken in the early evening purely with flash. It's important to note that using flash doesn't mean that your photo must look like you used flash! Not all images taken at night have to look at the Echeveria flowers photo below (bottom).

Now that it's winter time, some of us have grow light setups which also serve as very good light sources for photography. If you have daylight spectrum bulbs, it'll make things a lot easier too.

For example, I moved this Adromischus below to the edge of my lights to help give a bit more depth to the photo.

Backgrounds:

Have to admit that I'm not a big fan of cloth or paper backdrops, mostly because they can get a bit repetitive over time. Whatever you pick, make sure it's simple and uncluttered to best show off your plants. Remove or crop out any distractions.

Normally I'm using my light wood deck, the walls in my loft, or my countertop as a background. Sometimes I use the backyard trees or sky, but that is fairly rare and a lot more difficult.

For this Aloe flower photo below, I used a plain wall that was just barely lit.

Macro Lenses & Extension Tubes:

These are both very helpful tools for taking macro shots of your plants. I prefer extension tubes because they're a bit cheaper and a bit more flexible (with different length tubes).

Macro lenses can be very helpful, but they can get quite expensive if you are looking at the top quality ones. If you are using a macro lens, it's best to know the minimum focus distance.

I used three extension tubes stacked together to take this Neohenricia photo below. The flowers are just 5mm in diameter!

Focusing:

If I'm taking an overall plant shot, I'm using automatic focus on my camera. That's pretty straightforward.

But if you're planning on doing very close macro shots, I highly recommend using manual focus. Adjust your lens to its minimum focus distance (if you want maximum reproduction ratio) and then move your camera to bring the specific details into focus.

Often, the depth of field is so narrow when working at the macro level that focus ring adjustments are just too 'coarse'. Take a couple photos and review your photos to ensure the critical plant details are sharp, such as the leaf texture on this Haworthia below.

Depth of Field:

There is no hard rule on what apertures to pick when taking photos of your plants. I would recommend picking a small enough aperture for sufficient depth of field.

This would be say at least F4 for overall shots and at least F8 for macros. Note that if you stop down extremely small, say beyond F16, you will end up degrading your image quality instead due to light diffraction.

It's always a bit of a trade off. If you are really particular, you can try specialized techniques like focus stacking.

On this Lithops photo below, I wanted just enough depth of field to get all the anthers and sepals in focus. Everything else was less important.

Colour Balance:

Generally, I like a bit of a warmer tone to my images. It's all personal preference really. The big part is to correct for any strange light you may be taking photos in, particularly if its incandescent.

Often I will use 1/4 CTO gels on my flashes to warm up the light just a little bit. If you are able to take RAW photos with your camera, it is a distinct advantage.

And that's it for my introductory tips for plant photography!

I've hit my post picture limit and run out of time for now. Hope that helps! =)