Defoliating will harm your plant and not help with making it bushy, just the opposite in fact.
More leaves = more energy being made = more growth.
Less leaves = less energy being made = less growth.
"Tip pruning" if you are growing a photoperiod plant may help, but if you are growing autos, just use LST and let the plant do its thing.
Good lighting and proper care is the best thing you can do for your plant, there are no magic techniques or short cuts that will turn a normal plant into a "super" plant.