"learn to say no" is critically important, but can seriously damage relationships with colleagues. I have found that it is important to explain very carefully a

"learn to say no" is critically important, but can seriously damage relationships with colleagues. I have found that it is important to explain very carefully and ahead of time why you will often be saying no, and try to mitigate its impact by, for example, having a disciplined daily window when you're saying "yes" a lot or queuing work for that slot when it is not 100% urgent (ascertaining the real urgency of requests is also a major skill). I have found that it is possible to improve one's own productivity, but reduce team morale, when I am seen as obstructive or not a team player when I "NO" too much without mitigation / explantion. Said explanation should always include reasoning about why your progress is aligned with team progress, even obliquely, but it can be a tough balance.