1. Pruning and topping
2. Add a flower booster grow light
3. Correct type and amount of nutrients
4. Harvest the plants at the right time
1. Topping to increase the number of colas
Prune to clear off dead leaves to help your plants focus their energy on the live parts of the plant. Prune large leaves which get in the way of light reaching the colas.
Topping is a form of pruning and involves pruning off the branch tip of the main cola. When you top the main cola, the energy goes to the side branches. The next two lateral branches will become the main branches.
Topping will increase the overall yield of your grow. Although one shoot will produce a more massive individual cola, topping will give multiple colas with a higher combined weight. More colas will get more light than one large cola, and the cumulative yield will be higher. Do not top your plants more than two times per grow. When you trim a plant, growth will slow initially, but the plant will eventually become stronger and yield more.

The main cola is pruned so the lateral ones will grow; Image courtesy of DormGrow
2. Add a G8LED Flower Booster Grow Light

G8LED 90W Red Flower Booster light; Image courtesy of DormGrow
Increasing the light intensity for the plants at the correct time will add size and weight to your yield. The G8LED 90W Red Flower Booster grow light is an extremely effective light that should be added during the flowering phase.
The Flower Booster can be used with LED grow lights, HPS bulbs, metal halide lights, T5s, CFLs and plasma indoor grow lights. The 90W Red Flower Booster