Happy new year! I'm not really the type of person who chooses specific resolutions at the start of each January (also, it's the middle of January right now anyway), but I do have one fairly large ongoing goal that I'm currently trying to incorporate into my life and especially my work: stop giving in to other people's urgency.
During the early years of self-employment it's easy to want to say yes to everything when you don't know when your next project will come along. But now, more than three years in, I am getting better at setting realistic expectations for when things can get done (and if those those expectations do not work for a client, I am more willing than I used to be to pass along the project to somebody else who might have more immediate availability).
If you're self-employed or even if you're just not great at setting boundaries with your personal time, here is some advice that I'm still trying to learn for myself: be clear about timelines and terms ("this project will take X amount of time, and this is when I can start"), and tell them what you need and when you need it so they uphold their end of the agreement ("if you need this finished by X date, I will need you to send me your feedback by X [earlier] date; if you don't, the deadline will need to be extended").
All that said, if you need something from me don't let this keep you from asking! I just might tell you "not right now, but is February okay?"