Tending to your bonsai can depend purely on the amount of time you want to invest (still consider though, that very few works are worthy of being considered a true bonsai, with some specimen being passed down between several generations). You're still growing a tree, you just need to make several adjustments as to how it is taken care of. This involves pruning, watering, adding fertilizer, and replanting as necessary. Some of these tasks are done on a nearly day-to-day basis, and others are done only once or twice a year if not with longer intervals of time in-between.
In nature, trees adjust to their respective environmental conditions by growing in a specific way, shape and size. A tree very high up in the mountains, with soil that isn't rich in nutrients, has little rainfall, and less oxygen by the nature of the altitude, readily grows in the style we desire to replicate. The first part of your journey is choosing your own tree. Oriental philosophy has you traveling into the wild for weeks at a time to find the one tree that is worthy, but now-a-days you could just as easily buy a starter tree at your local gardening store. Those of you who are more adventurous, can grow from seed or propagate a branch you've collected.
Did you have a specific species you want to work with Barmymoo? And as for your question, that depends purely on what type of a tree it is.