Learn the Prerequisites, Not the Whole Universe

Before starting something advanced, you naturally look up what you need to know first. The problem is that this search never ends. The prerequisites have prerequisites, and those have their own prerequisites — before you know it, you've mapped out a twelve-month study plan for a topic that requires three weeks of background. Identify the 3-5 things you genuinely need to understand and learn only those. Everything else can be picked up as you go.

The instinct to learn everything first is a form of procrastination disguised as responsibility. You'll never feel fully ready, and that's fine. The gaps in your knowledge will become obvious once you start the actual work — and filling gaps you've experienced is far more efficient than pre-filling gaps you've imagined.