The key to a large harvest of tomatoes is to grow plants with deep, extensive root systems and full, leafy canopies. Here are two ways to help your tomato plants be as healthy, and productive, as possible:

Pick off all flowers until the plant is at least 1 foot tall, that way the plant doesn't devote energy to forming fruit before its roots and foliage have filled out.

Prune all the suckers as they start to grow. Suckers are the sprouts that come up between two main vines. Suckers grow quite long before producing their first flower cluster. By removing them, you allow your plant to use that energy to produce additional flower clusters elsewhere on the plant.