When you enter the deployment phase and are ready to jump from the transport plane with the other players you need to avoid jumping with a large group. The other thing you need to be doing as you prepare to jump is look for a lightly-developed area that has a few buildings which not many other players are disembarking above. Remember that you will need to travel to the center of the map so don't choose somewhere too far away. When you have picked the place you want to land you need to jump out the transport plane and press the FWD key to aim yourself towards the ground so you get there as fast as you can. Your parachute will open automatically at 500 feet up.
As soon as your boots hit the surface you need to get inside the nearest building as quickly as you can. Buildings will give you cover from enemy fire and once inside you need to search them for weapons, equipment, and other useful items which you can loot. At the start of the game all doors are closed so if you find a door open you know someone has been there. This makes closing a door behind you after you have searched a room a good tactic as it doesn't alert other players of your presence.