No matter what you do with drywall there is always going to be big crevices and spaces that need to be filled in once you cut your holes for your drywall. Basically, what I do is after I put a coat on and I'm getting ready to put a second coat on, I take all the extra mud and I run a round and fill in all these places so that once we're done here everything will kind of be filled in or at least we will have the first part of the coat ready to go.