Every 20 kills you get a special item which you can drop on the ground. Allies can choose this as a spawnpoint.
A player-made spawnpoint can be made by making a 5x5x5 box with 1 3 block opening using red blocks. The game checks for this type of building, if it is there people can use it as a spawnpoint. because it is a 5x5 box it will require travel back to a tent for resupply, which in the meantime, can be destroyed by enemies or trolls :l