Professionals, unlike amateurs, spend their time carefully. They prioritize because they know they can’t put their best effort on everything. Businesses put it like this: focus on the 20% that makes 80% of your profit.
If you are serious about your work, track how you spend your time, at least for a week. Review your data, identify your leaks, and then decide what you are not going to do.
I don’t know the key to success, but the key to failure is trying to please everybody_1. Deciding what you won’t do is the hardest part, because it not only implies saying _no to yourself, but to other people’s expectations.