Just start. Even spending a few minutes on a problem you've been avoiding will help make the issue clearer, plus you're more likely to keep going once you've started (see also: pomodoro technique).
100% agreed. I can get very resistant about doing some things. Committing to doing one pomodoro today has been very helpful. At worst, I've broken my not-doing-it streak, and it will be easier to return to later. And at best I'll get into it and charge on through.
