Split up work such that each PR is small and focused. This makes the review easier to complete.

This is especially important when refactoring. Refactoring PRs are vulnerable to falling into merge-update-review cycles.
1) You finish the refactor and post the PR.
2) Before the PR is approved, other devs check changes into Master.
3) You merge the changes into your branch, and have to integrate your refactors into those changes.
4) You have to run all tests again, and the PR needs to be re-reviewed.
Back to step (2)