Weapon
Pistols
There are many pistols in the game, but the best one is the M17 as it deals decent damage in the early stages of the game.
Submachine guns
Good for close combat. In H1Z1, the Hellfire is the only weapon worth taking with you as it deals massive damage.
Shotguns
Well suited for close combat and early game battles, when enemies are still low on armor and can be killed with one shot. The best option is the Combat Shotgun. Although, if you plan to fight at very close range and are confident in your goal, the Riot Shotgun will do.
Assault rifles
The best assault rifle found in all air-dropped crates is the AR-15. It is perfectly balanced for the early game. However, in the end the KH-43 will be your best partner as it has low recoil and good damage.
You can also take the Marauder, due to the high damage, but it lacks automatic fire, so it should only be used by those who are confident in their goal.
Sniper rifles
The M40 works best as it has a long range and you only need two shots to kill an enemy.
Finally, both explosive bolt crossbows and the MK46 LMG are suitable for vehicle destruction.
Technique
Police car
The best car in the game as it is very well balanced and very fast. It is best used on asphalt as it can roll over when off-road.
Jeep
Nice 4-player car that is great off-road. It is very easy to drive and will only be slightly slower on tarmac.