Not any good advice per se, but a funny story...
I did my first blue belt tournament yesterday after only having my blue for 1 week. 1st match I pulled guard because I'm not confident in my stand up. My instructor gave me shit. He said it's a poor strategy unless your opponent has vastly superior takedowns. He told me mine were good, so use them. Good advice.
So next match comes and I decide I'm going to get a takedown. Well, that didn't work. Next thing I know, about 5 seconds into the match I'm flying through the air after a judo sacrifice throw. I'm 6-4, it was something spectacular me going for a ride like that, lol.
Turns out this guy cross-trained BJJ and Judo, I should have pulled guard, lol.
Anyway, that's my story on how I was put on the mat VERY quickly.