XP

The best way to improve yourself, is to challenge people who are better than you. Only by analyzing why they are better and why you may have lost, can you fix those mistakes and improve yourself.

I have gotten into the habit of challenging anyone I'm at least somewhat familiar with in any kind of skill related task whenever I'm bored. This could for example be in chess, checkers, connect 4, foosball, and even card games. I'd be up for basically anything that isn't pure luck based. It's just a great way to pass time. If your friends aren't able to beat you, you just need to teach them how they could potentially have beaten you. Eventually they'll hopefully reach a point where they will be able to take advantage of your weaknesses and thus force you to improve.