You have 50 team members. That means team work is going to be more important than ever, because the enemy will have 50 team members too.
This means stick with members of your team, make sure to revive team mates, and share weapons, shields, and fortifications.
If you can get to the circle early, start building and get ready to defend from enemies moving in. Although, with the next tip, they'll be coming from more locations than just on the ground.