I'd add 7) Try not to make the same bug/mistake twice. One of the most important things I learned from chess was to go back over your previous games and look

I'd add 7) Try not to make the same bug/mistake twice. One of the most important things I learned from chess was to go back over your previous games and look for what mistakes you made, why you made them, and how you can avoid them next time. Do this same analysis with every BUG you see a bug in your code(whether you wrote it or not). Ask yourself why you or someone else make this mistake? What is because they a assumed a method did something it didn't? Was it because the domain logic wasn't in a single easy to find place so they reinvted the wheel and did it incorrectly?