ok you need a party with 6 players and do headquarters i say this because if you can capture all bases and keep capturing them you will rnak up fast i did it in 9 day play time and also buy contracts you might not think they will help but there do when you have almost completed a 1000 contracts youll see that youve gainded almost 1.000.000 xp and almost 500.000 credits remember go for kills if defending the HQ if not defending the HQ then dont got for kills always capture HQ you get 5000 for caping then bouns plus kills with a good team of 6 youll get 8000-1000 depending on challenges each game will last about 5 mins unless you play search and destroy you can do good but if you die not so good HQ is fast for all