I suck at debating how to improve?

I have a hard time expressing my thoughts and I‘m never brave enough to actually say something during a debate but it’s SUPER interesting to listen to others debate it‘s genuinely the coolest thing to be able to do in my opinion. My question though is how do i get good at it because most of the time people already expect you to be „good“ at debating and I have this fear that I won’t be able to respond to anything because I‘m just too slow to get it and make up a logical thought. Anyyy tips