How do I get bushy plants?

How do I get my plants to be more bushy and full? Any plants i've grow so far don't seem to be as 'full' as most i see meaning they have few branches and such? is that because i am growing from seed and not clone?

no, it has to do with how easy it is for the plant to get the light it wants, more light and making the light close(2-5" away) makes it so the plant doesnt have to stretch as much... and the strain has a lil to do with it. put a couple cfls surrounding the plant from seedling.