Check out the Rationality: A to Z contents page, click on things that look interesting, it'll mostly work out.

A Human's Guide to Words is really good exposition of philosophy. The subsequence of thinking about morality that I can point at with the post fake fake utility functions is good too. Or if you just want to learn what this rationality stuff is about, read the early posts about biases and read Knowing about biases can hurt people. That one's important - the point of knowing about biases is to see them in yourself.

I just don't know what suits you, is all.