Been coaching over 30 years. 20 as an assistant. Here is what I've learned. Feel free to add more
1. Its your head coach's program. However he or she wants to do things is the law
2. Respect the chain of command. Everything gets approved and run past your head coach first. Your head coach should always be the first to know
3. Never go to administration or another coach to discuss the program or other coaches negatively. Go directly to the source
4. Coach your kids. It's easy to complain but you'll get more respect when you can develop what you have
5. Earn what you ask for. You want a promotion or elevated title then earn it.
6. Show you can be trusted with the responsibilities you're given and you'll have more
7. Do your job. Whatever role or duty you have do it with a sense of urgency
8. Great head coaches will prepare you if you get out of your own way. You can't do your job and theirs.
9. All head coaches keep a short list in case you move on or if they have to fire you. Even nice head coaches. Don't be fooled.
I'm sure I'm missing a lot!