A little while ago, I read a very useful article that can be found here.
The key idea in the article, I believe, is that the best way to get better in chess, in the final analysis, is to go play; as opposed to reading books, studying all the time, etc. which the article makes clear is all very important, but which is all rather superimposed and secondary compared with playing.
The gist of what I took from the piece and a couple of the comments posted by users is that everyone can beat anyone else in any game. I found this to be the case. Okay, it is really easy to get it in your mind that hey, I’m going to lose this game—especially if you’re in a slump. So, just go to each chess game with a clear and fresh mind. Say, hey, I’ve got as good a chance of victory as the person on the other side of the board.
In the final analysis (to use this useful term twice), all one can do is go out and give each new chessing opportunity their best shot. What does it really matter who you’re playing?