Learn the idioms of the language you're using. Respect them. USE them! This seems to do wonders for improving the readability of your code, and makes it easier to put your ideas into the "words" of the language you're using.
Know when to/don't be afraid to put your code into functions. For me at least, 3-4 40-50 line functions are almost always easier to understand than 1 big honkin 200 liner that often seems to look ugly and repetitive.
Focus on producing *good quality* code, with less of an emphasis on how quickly you can churn it out. I learned that from this node. :) It's amazing how lots of careful thought about a problem, without doing any (or very little) coding during that thought process can suddenly turn into an elegant solution.