tip 1 : stay away from objective places, it will lure enemy away from those are doing objective and also will increase your survival chance (and score too).
tip 2 : run to the LZ as early as possible in extraction wave.
tip 3 : revive your team mate. does not matter if they are dying in a open space surrounded by enemies or in front of an sync killer. cause its a team game u dumba** !!
tip 4 : dont use your rocket in objective waves. let your team member do it, cause they are better using it than you. save yours for extraction wave.
tip 5 : always use missile on double banshee, they are too deadly.
tip 6 : try to stay alive. remember safest place in this are those box container in rio and lz of giant.
tip 7 : use pull on every deference type cause it staggers them.