I'm a big fan of bonsai too! I have two "pre-bonsai" plants (this means the they're not fully formed or in their final form but in the way of transforming to bonsai). One is a ficus benjamina and another is an orange tree.
A few tips I can come up with:
- Start with some cuttings (ficus is ideal for this, since it grows fast). The cutting size that work best is like 15cm of height x 1 cm diameter approximately.
- Plant the cuttings in a mix of soil and sand, the humidity must be quite high at first stages (90%).
- When they start to root, place them in a location where they get sunlight, do not overwater them.
- Let grow until trunk reaches the desired diameter.
-Prune roots and tree tops according to the style of your preference.
It takes time but its soooo cool