If you've been working on it for more than a week, then you've probably already taken a break. Usually that helps, but otherwise I like 1. trying to explain the issue (both the problem I'm solving as well as the solution) to an imaginary listener (or possibly even a real one, if I'm lucky) 2. try rewriting parts of the code, at least to get a minimally working version, ideally with a different approach. 3. try to draw/sketch what you're trying to do/actually doing

Life on the other hand, is a bit of a different issue. There's no real algorithm for that ^^