Finding good advice about how to get representation by galleries is kind of a tough thing to do. It's even possible that it may not be a good idea to try to find a gallery to represent you.
At this point in time with Covid and the partial collapse of the gallery scene due to Covid and the fact that artists may be better able to represent themselves better using the Internet, than using galleries.
I offer a free class here with a bunch of videos about the business of making art.
I've also collected a series of videos here that I think might be useful for you to watch.