usually when you cut the top off it will branch out, or at least start two tops. most people say that after 3 sets of leaves you can top your plants. i always do this because it keeps the nodes a little closer and i dont need real tall plants, it stunts them a little. and i usually do it at least one more time on all the branches before it starts to flower. it wont hurt to trim off some leaves, but if they arent bothering anything leave them because they soak up the light.