I'm no expert, but here's my two cents:

First, make sure you bury part of each rock. Leave 1/2 or 2/3 sticking out. Natural rocks are usually partially buried. If you don't bury them, they look like they fell out of the sky. Plop, plop....PLOP!

Also, if they have some sort of grain or layers to them, make sure the grain's going in the same direction for all the rocks. It makes them look like they formed there, rather than being moved there.

I'll let you decide on the plants and fence. I don't really like fences, so I'd leave it out. But that's just me.

-Rob

I'm with Rob about the burying of rocks, I would like to add that if the rock has a rounded side and a flat side, setting the flat side down usually looks more natural, and the rock won't need to be buried quite as much, but so much depends on the types of rocks.
You can use different types of rocks and mix the grain if you want to make the garden look more like an old flood area where the stones were brought together by water flow. This is how my most recent rock garden was designed, although the colors and textures were similar.
The only type of fence structure I like in my gardens is the 4" round or square posts set upright, side-by-side, at differing lengths, but it stays low, no higher than 24", and tends to meander.
I would have had some pictures of this last garden to show, but ding-a-ling me took pix with no film in the camera, but I have some other rock gardens on my Webshots albums, these made with our local limestone.

Here is a link that might be useful: My Gardens and More