First, do your formed cone technique. After that, You should be applying 2 lbs of pressure when you condense. (Someone correct me if I am wrong, but I think I remember that right.) Get a little postal scale to feel what it is like. It is probably more than you think. You don't want to do more, for risk of fracturing the root, but doing much less is an easy way to keep voids. Then, instead of pulling the condensor straight out, try rotating it back and forth to slowly loosen it out. I also keep my other finger on the gutta percha to avoid pulling it out.