•During Gold Rush, you dont need to kill every enemy you see. You should just kill the enemies that get in your way.
•If someone goes down, both people need to go help them because if that person goes down, your probaly too far away to save both of them. On round 6+ of arena, dont be so close to each other that one rocket/grenade can kill all of you at once.
•During Gold Rush, score the treasure quickly because then there is a less chance of someone dying.
•On arena crushing, kill the bosses fast because they are the most danger (with the exception of a brute).
The best tip that I can give you is to practice. Practice, practice, and practice.