Why do I keep hitting the rim of my racket in badminton? What can I do to improve?

I hit the rim a lot in badminton. I swear, if they made the racket a bit bigger and in a donut shape I would be a world cl player. I think it has to do with my timing, like I'm not waiting long enough on a dropping birdie, or not reaching far enough to block smashes... But sometimes, when the birdie is dropping slowly from the sky, I tell myself, WAIT!!! And I make sure that I will hit it in the sweet spot. But then, PLINK, I hit it on the rim again. This really annoys me. What can I do to improve my play?