The quickest way to learn to beat a stronger player is by losing to him, but understanding why you lost. This way you know what to work on so as to increase your chances of winning next time, or at some time in the future. It's a continuous learning process, and players who improve rapidly are constantly learning. For example, if you had trouble with a specific serve, or a spinny loop, or a heavy push, don't just complain about it - find a top player or coach who can mimic that serve or technique and practice against it and turn that weakness into a strength. If you realize there's a serve or technique you need to develop to win, then develop that serve or technique. If there are tactics that you think you need to develop to win, then try them out in matches and see what works. But it all starts with learning from your matches, and especially your losses, so you can identify what you need to work on. All these bits and pieces learned here and there add up to a savvy player.