Keep trivial changes like renaming, reformatting, moving code around in its own Pull Request (PR) ; Keep refactoring code in its own PR; Keep rest of the code in separate PR. Combining these three will dilute PR, people either won’t review by looking at sheer number of changes or will leave too many comments ending up in a myriad of ping pongs resulting in overall compromising tiresome experience.
Keep smaller PRs, Keep them to one issue (or minimal logical conclusion of feature) ;
Try to develop one or two buddies. This greatly improves turn around time of your PRs. Of course you need to reciprocate the same.