Everything that has been said is great advise but really, my .02...
1. Learn when FLCH and FPA/VS is appropriate. The vertical planning part of the PFD is a great tool.
2. Slow down early, don't be afraid to use boards. Eventually you will get comfortable with the airplane and keep it faster and faster.
3. Ask your CA if he/she has any tips or things you could be doing better. I always told them I was new and would appreciate any advise. There are a hundred ways to fly this plane, take what you like and disregard what you don't.
4. If you ever feel behind the plane or lose situational awareness, don't wait until you are filing an ASAP. Speak up.
5. Ask plenty of questions. If you are PM and see the CA start pushing buttons, ask what he/she is doing.
6. If you use the side bag strap, be courteous and undo it.
7. Never remove the empty cup in the cup holder. It's there for a reason.
8. Always leave the cockpit clean and ready for the next person.