LST.

Low Stress Training, you tie down the top of the plant to create an S shape in the stem. what this does, is opens up the lower branches to the direct light (before the canopy of the top was blocking alot of the light). Not only is this better because you keep the top, but it promotes the side branches to grow alot more because they're now open. your yeild will increase, the over all health of th eplant will increase, and it's a great way to regulate the height of the plant.

Don't forget the plant grows about 30-40% during flowering.