I wrote a thread about this but I think it was lost, anyway, here is what I do...
Get a big piece of fabric and hang it up from something so that it makes an 'L' shape from the wall to the floor, try to make sure there are no creases in it. This will be your background, and a clean, simple background makes all the difference!
I suggest placing your fabric sideways on from an open window, or you can set up a lamp or two near your bun (make sure the cable is out of his reach).
Don't use flash unless you have to, it is much better to have enough natural light, as flash makes photos look washed out and casts heavy shadows.
I like to put ribbons or flowers on the 'backgrond' to make it a little more interesting, and it gives the bun something to play with!
Lastly, a border is a nice touch with a photo editing program.
By doing this, even photos from a phone can look great.
Here are some examples of photos I have taken this way (these were taken using my DSLR, but I have taken shots in between with my phone and they come out almost as nice!).
Editing with photoshop or something similar can make a huge difference.
***If anyone would like photos retouched I will do it for you, just send me a PM!***