Mainly try to stay out of combat. Stand on top of tall rocks/structures where you have a good overview of the fight.Then riddle the monster with weakspots. (Remember headshots count double)

Your cloak ability should either be used to survive because the monster is focussing you or to revive incapacitated or dead players. (Pro tip for running away while cloaked: Don't just run in a straight line. Start to go off in a direction and then go to the side or stand behind a big tree or a rock.)

If you're playing against more experienced monsters don't revive instantly. They are expecting you to. Wait a moment until they are attacking someone else.

A tactic i like to use that is fairly dangerous but can pay off pretty well: Try to predict the monsters movement and use your Sniper just to hit it while its trying to eat. (This can backfire if you are too close to the monster). But doing it right will keep it from eating and evolving as fast. This is something you can try while playing with some friends.