As you play, you will have to worry about four main things; Irradiation, hunger, thirst, and health. Irradiation is the hardest to take care of once you progress. If you get into battles with hoardes of zombies, you can easily die due to radiation sickness.
Health is also pretty dificult to take care of, but not nearly as much. You can heal from eating, using medkits, and a few other actions. Hunger and thirst are the easiest to take care of. You can find canteens, and fill them with ocean water to avoid having to find bottled water or soda. You can also grow crops, and cultivate a farm at a location of your choice. A few tips I can give are:
Set up a base away from zombies or towns, they can attack and destroy crops, and bases.
Be sure to NEVER provoke zombies once you first start with no weapon, unless you are an older player.
Also, make sure that the first thing you do is raid a farmhouse, you can find arrows, bows, guns, axes, bats, chainsaws, etc.
You will sometimes find what I like to call the "Hulk"
It is a zombie that is larger than normal, and does alot of damage. If you try to fight him, be sure to kite him, or just shoot him.
If you don't know what kiting is, it is when you allow the enemy to attack, and when he is done attacking, stab him, then quickly run back before he hits you. Just do that continuously to kill him.
The "Hulk" can drop a variety of military grade weapons. You may find that the most prominent of all is the "Dragonfang"
The Dragonfang is an LMG, with a magazine size of 100. Also, there is crafting in this game, which is much too complicated to get into on a post, but i can say that you can repair weapons, craft barricades, walls, doors, roofing, gun attachments, apparel, bandages, and many other things.
Also, be sure to check out the airport or military base when you get very good gear.
If you find any of what i said intrigueing, then by any means necessary, get this game.