Just duplicate whatever is working. If you have 20 Adsense sites that make you a total of $200 per day, just build 20 more using the same strategy and there's no reason why your income won't go up with it.
I'm sure you've probably heard it a thousand times by now..."find out what's working and scale it up". It sounds simple, and it is, but that's really all you should need to do especially since you found something that works.