Test your code, every which way. Think of edge cases, security holes, do research on how code fails and internalize those lessons, and constantly test - test te

Test your code, every which way. Think of edge cases, security holes, do research on how code fails and internalize those lessons, and constantly test - test test test. Manual tests, unit tests, etc. Code that works reliably is (IMHO) better than beautiful code that doesn't work at all, or falls apart under strain.