I've decided to re-focus my energy to maintaining the top position, instead of just gunning for the submission right away. I find that when in a bad position, people will try their escapes two or three times, then give up. The better players await for the top guy to make a move,then apply for something. This second category is trickier to control, since you might think you've defeated them mentally, but in fact they're just baiting you into trying something.
I will continue sweeping from my guard, though, but I want to get the side/mount position and hold it as much as possible, while making the guy's life hard so he makes mistakes.
When playing guard, I will let people pass or sweep me first, then let them apply for a submission, so I can practice my submission defence and escapes. It's no use beating everyone up all the time if I'm not learning much. The point is to maximize learning, not taps.