Unturned Multiplayer Tips
If your new to the server do some scouting
If you have joined a new server, find out a bit more about it. Find out if it has kits, teleportation, economy ( shop ) etc. Go around and work out who plays regularly on the server and who is likely to kill you without you even noticing, this will help you to know who to stay away from and where you should go - preferably quiet places. On the server it wouldn't be uncommon for there to be some other beginners but chances are there is going to be at least one of those people who everyone stays away from and always kills on sight with whatever gets in the way - just to clarify, don't kill these people unless you are going to kill them instantly, if they know where were shooting at them from, chances are they will hunt you down.
If your building a base have a friend with you
This will increase your chances of survival when building the base, find a time when both of you can play for a while and start. One builds whilst the other looks out for enemies. If your going to get attacked your friend can tell you and can defend rather than you just being killed because you didn't see them coming - that's the point of the lookout. In simple terms; it is safer.
Kill on sight
I am one of those people who doesn't shoot anybody just because they say that they're friendly; normally this ends up with them killing me. Even if they are totally naked and they have their hands up, kill them, unless you have handcuffs or a cable tie. For me I regularly get tricked by the fact that it looks like they've just spawned in and I get tricked because the gun they had was in their inventory meaning I couldn't see it, then I turn around and start to walk away while they take out their gun and place a few rounds in the back of my stupid head... If they are your friends obviously don't shoot them and make a group together to disable friendly fire and in addition to that, there will be a name tag over where they are even if they are on the other side of the map.
Defend your property
Simple enough, if you have a base then put defences around it such as spikes, barricades, fences, etc. for vehicles though just put wood panels on them making them harder to destroy but also less vehicle like. Another way how you could defend your base/home would be to make large wooden panels ( preferably maple ) into an arrangement to make a wall - side by side - then leave a hole to put a door frame in and maybe also another larger hole for a garage frame so you can put in a double door or a typical garage door. If you can then build out of metal or a better wood as this will increase the strength of your base making it harder to break into - keep in mind that other players can open wooden doors, garage doors, etc. so make those out of metal because then they need explosives to get in, or maybe just climb over the fence if they have some kind of way to do so - there is another reason to why you should have barbed wire fence or at least barbed wire along the top of the wall.
Be prepared for the full moon
If you find yourself in the position that you are being chased by 500 red eyed zombies then you will probably die - unless you are prepared. In Unturned whenever there is a full moon, all zombies get stronger and can detect you more easily. You will know that it is the full moon by 3 ways; you see the full moon icon above your life statistics ( health, hunger, thirst, immunity, stamina, and oxygen ) , or you will just see that it is a full moon, or you will se that living zombies have glowing red eyes. Check through the night how close it is to the full moon so you will know when to not go out scavenging for tape, if you are going to do that, make sure you bring a gun with plenty of ammunition or a high damage melee weapon for the silent option. In addition to thinking about the zombies wanting to kill you remember that there are also other people on the server who will want to end your life. Because it would be a full moon, killers would prefer to go hunt as a sniper rather than walk around with an assault riffle so be careful where and when you go out of your base.