Try the FIM technique if you're looking for bushy plants if you're vertically challenged like me.

I have two plants with 4 colas each about 18 inches tall. Just make sure you prune lower branches to encourage the 3-4 primary colas to be the focus of the plants energy and do so after the 4th set of true leaves have established.

Jorge Cervantes has some decent info on the FIM technique if you want to learn more.