layout root title lesson . The Rules A week of hard work can sometimes save you an hour of thought. Fail early, fail often. Turn bugs into assertions or tests. Red, green, refactor. Always initialize from data. Test the simple things first. Know what it's supposed to do. Make it fail every time. Make it fail fast. Change one thing at a time, for a reason. Keep track of what you've done. Be humble. Throw low, catch high.