Ahhh Fimming...I remember reading alot about it on the old Overgrow.com site....seemed like an elusive holy grail. As I remember, proper fimming is as Jonda mentioned, where you cut out the tip of a main main branch, but leave just enough so it branches into many cola tops, like 4 or 5 or more. I've never been successful at it myself. If you pinch the lead growth back with fingertips, it WILL cause that branch to split there giving you two tops instead of one. If you get it to work give us a pic! Good luck