Some questions for any experts who may lay some of their knowledge unto me.

I'm pretty newb to airsoft as a whole so yeah... HALP
I just got a TM MP7 ordered fresh out of the box, $500+, but I like the gun and the only place I go airsofting ATM is at indoor arena, so it's perfect for me!
Anyways, considering I'm investing a bit in this guy I would like to know:
1. What are the simplest things you can do to extend the life of your gun?
2. What does cleaning do other then make it clean? :/
3. Any other tips to give my gun a healthy glow?
Thanks!