From lessons I learned in HPMOR before making an important decision ask yourself "What do you think you know, and why do you think you know it?" I have found that this not only shows you what knowledge you have is sound enough to make decisions on but shows which pieces of knowledge you're emotionally attached to and would therefore lead to a biased conclusion.
I'm not as smart as I like to think I am. Knowing that, I've gotten into a habit of trying to work out as many general principles as I can ahead of time, so that when I actually need to think of something, I've already done as much of the work as I can.
What are your most useful cached thoughts?
A few of the rules-of-thumb I've already pre-cached include:
That should be a reasonable but not overwhelming sample of the sorts of ideas I mean, and am hoping to evoke more of with this post.