Qd8+ Qxd8 Rxd8+ Kxd8 Bxf6+ wins a knight
What would be the best move in this situation?

9. Qd8+! Qxd8 10. Rxd8+ Kxd8 11. Bxf6+ and 12. Bxh8 was winning a knight.
9. Nxe5 was winning a pawn (9...Qxe5?? 10. Qd8#).
Similarly, 9. Bxf6 Qxf6 10. Nxe5 was winning a pawn.
In such positions, where you have a lot of pieces well developed and your opponent barely has any and his king is stuck at the center, there are often some decisive tactics possible, so that'ts the first thing you should be looking for. Barring that, sometimes positional sacrifices are possible: you can give up one of the light pieces, for example, to open the position up and to use the exposed opponent's king to your advantage.
Hope it helps.
Hello, I'm a beginner, and I was playing this guy as White when I honestly had no idea how to attack in this position. Eventually I won by him timing out, but what should I have done? A lot of times I'll get stuck or make a lot of blunders in games like these. (I also know I shouldn't of tried to pin his queen with my bishop because he could of moved his pawn up.) Any suggestions or advice in general? Thanks