I have been flying for about a year now and had the same problem. In fact, I still don't hit a landing perfect every time, but am reducing the number of landings where I bounce a lot. Even with all the suggestions here, the best one is practice, practice, practice. No system, or technique will work well without it. It is like everything it takes time. Also, my instructor agrees that slipping is an advanced technique and has not taught it to me yet. I'm getting close though.