What I try to do is ignore the behaviors I don't ask for. My Boxer Jinx is good for this. If you say 'sit' then they down, stand, bow then sit. Ignore all down, stand, bow but praise or rewards very very heavily for sitting. "Laws of Lazyness" will show up about now. They are learning they do all this work for nothing, then they'll either show down their other behaviors or getting rid of some. Instead of doing down, stand, bow and sit then it will just be down, stand, bow and sit. Soon it will just sit when asked. The tedious thing about this you might have to do the same for a few behaviors.