Communication for Developers: estimates, code reviews, and other hard problems

For many of us, writing code quickly becomes the least of our concerns. Let's talk about something that can be much harder: communication. But don't worry, this won't be yet another abstract talk delivered by a couch.
Instead, we will touch on subjects directly related to the developer's life: code reviews, git commits, managing your manager, talking to the product and business people, estimates, or knowledge sharing.

How to get your PR reviewed without much waiting?
How to review the PR without making enemies?
How to respond to estimate requests without making (unrealistic) commitments?
How to keep necessary people in the loop without creating unnecessary noise?
Let's try to answer all of those questions and more!