This is the best article I've found on photographing bonsai specifically:
http://www.artofbonsai.org/tutorials/photoguide.php
HOWEVER, taking a picture of your bonsai is nothing more or less than still life photography, and every basic photography book has at least one chapter on that subject. Check your local library.
It doesn't really matter what kind of camera you have, EXCEPT that the camera on your phone isn't meant for this kind of work -- and be CERTAIN the your pictures are right side up! You will be better off with a real camera. And then, learn to use the software that came with it! If this 76-year-old technophobe can do it . . .
Keeping in mind that most of my bonsai are under 2 feet in height, here's what I have:
For a background, a white matboard, or the natureal yellow wall, depending on the tree and desired lightng.
Coming in from the left, natural light through a glass door and either from overhead right, or from the right front, an artificial light and reflector. Most of the time I use overhead right (first picture).
I do NOT use flash -- not ever.
Piuctures of the setup and some results.