Ask questions at the beginning of each project. Ask as many questions as possible: How, when, why, for who, etc. Gathering information by asking gives a better overview, clarifies what should be done, and helps to be at the bottom of things every time. Whenever someone asks you about something - you will be well-prepared.
Basically, we can start every project very fast, with a short brief only. However, in my opinion, a better understanding of a project gives us more confidence in making decisions and introduces us as professionals who know what they are doing. So it does not matter whether you are a UX designer or UI designer - do not be afraid to ask questions.