[BigJ]

Comments and Documentation: Use them! You would never believe how fast you will forget how something works, especially when things are flying at you so fast. Other/future programmers will understand what you did and why you did it.

Become Intimately Familiar: The more you know how your system works and how it should work, the more help you can be in diagnosing problems down the road.

Stay Open Minded: There will be times when everyone but you says "it's gotta be the code". You'll be 100% sure it isn't the code. Everyone else has to be wrong. Listen to them and give their theories a shot. It's probably the code.