There's a couple of real easy things you can do...
1. If you are using a briquette like kings ford switch to the copmpetition(at least) or a lump hardwood charcoal.
2. Add more wood. This open is a pretty simple idea, more wood = more smoke
3. Start with colder meat. Go right from fridge to grill don't let it warm up first. This will take a little longer but will give you a deeper smoke ring and longer time for the meat to absorb the smoke.