What kind of light are you using? If it's a CFL, then 6 in. is too high, and you're probably getting some stretch. Hard to say without pics.

If you want to post pics, upload them to photobucket.com, copy the link, and at the top of the reply box is a picture of a globe with a paperclip. Click that and paste the link there.

You can make your plant more bushy with LST (low stress training). There are several tutorials on it around here (I gave a description of how to do it in the first link in my sig). It will help your yield...