Watering is very important to bonsai care. You could potentially kill it with lack of water. Below describes how to water properly and care for you bonsai. It recommends watering the pot, the tree, and the soil.

I've got complete information about bonsai tree from wikipedia and I think its the best source if you want to know about bonsai in detail. 

Bonsai trees should it the light for about 12 hours each day. The information that I found said that a growing light would be best for the trees. I also found that distilled water works best for the trees and they should be misted everyday if possible. Watering should be done once a week and fertilizer should be used two times a week, but only done lightly.