Recently i reset from master, i'm finding it troublesome to level up above 40, if anyone could help me it would be great.
I always got a lot of XP from playing objective modes like Demolition where you can extend the time limits by blowing up the bomb sites.
Hardpoint or League Play are probably best for points. Hardpoint has the highest SPM of any game mode and League Play is 7,500xp for a loss and 10,000 for a win. Run UAV, Counter UAV and VSAT (obviously not in league, lol) and bring a couple of EMP grenades for extra points from team mates too.