This is a relatively simple guide made for players who are either new or prefer the construction / survival aspect to the game over PVP.
Introduction
I am what many players would consider to be a "griefer", this is not entirely true. I have nearly 200+ hours on the game and have experienced both ends of the griefer / non-griefer spectrum. I am a big Mount and Blade player, coming from a small mod known as "cRPG" which is a very niche strict PVP mod within a strict PVP game. I enjoy fighting people and more often than not they do not enjoy fighting back, more often than not threatening to have me banned. I want to help people learn how to properly handle these situations, as it seems many players are uninformed on the subject.
Griefer or player killer?
There is a big difference between a griefer and a player killer. LiF is at least 50% about killing people, which is why a combat system exists, and killing people on its own is not griefing.
Griefing would consist of:
Deconstructing buildings
Exploiting over / through walls and buildings
Building camp fires all over your base
Tunneling under walls / in your base
Combat logging
Running into water to avoid combat
Using any existing exploits to get an advantage
If somebody is actually griefing you, you should probably tell a GM.
If somebody is attacking or stealing from you, you probably should not.
How to stay protected.
Even if you are not actively attacking people, you should be prepared to defend yourself. Make some pitch forks, or if you have the ability to use better weapons, use those. Metal hatchets work quite well in combat too.
Build walls, but be prepared for them to be disregarded. If you want to protect your goods, you can do a number of things.
Hidden loot bag - can easily be detected and looted, only use this if desperate.
Inside of a house - much more safe than a hidden loot bag, make sure to place the bag in the middle of the room and not near the walls / windows. Houses can still be breached by exploiters, so don't be too surprised if you still get robbed.
Warehouse - 100% safe as long as you keep it claimed.
Sieges / wall breaches.
Do you have walls? Good, but you're still not safe or even remotely prepared.
There are many ways to get over a wall currently, some are most definitely griefing and some are not.
If somebody uses /stuck or reconnects to get over your walls, it is griefing.
If somebody has logs floating in the air to get over your walls, it is griefing.
If somebody uses pounce / lunge (middle mouse button) to get over your walls, it MAY be griefing, varies from server to server.
The best server rules I've seen so far allowed logs to be stacked in any way as long as it was done logically. They had to be touching, and could not be magically floating from end to end. This takes awhile to do though, so if you have any ranged weapons, shoot them.
Combat 101
Combat is tricky in LiF, most experienced players use a number of tricks and maneuvers to get the best results, but this is not entirely necessary.
1. Pitch forks are good against lightly armored people. You should only thrust with your pitch fork, so spend some time getting used to the controls. By default, looking up while left clicking will prepare a stab, I suggest going into your options and inverting your swing directions. This will make you stab by looking down.
2. STAMINA is key to all combat, do not sprint with your weapon out or swing held unless you are VERY close to hitting your enemy. Most of the time I don't even take damage in combat, this is because most people can't manage their stamina properly. Sheath your weapon and sprint away, catch your breath, and wait for them to run out. Turn around, stab them in the face.
3. Speed bonus is very important, if you're using a sword, turn your mouse with your swing to improve it. Wiggle your mouse around when stabbing to get more damage.
4. Bleeding is bad, if you already had low health and have a high magnitude bleed, you're done. If you can get out of combat, do so, as it's the only way to save your life.
Ultimately, remember that it's an alpha.
I've discovered a number of bugs and have reported all of them. LiF is not a PVE animal farm simulator. There are many bugs to be found in all of the features, and sometimes the best way to find the combat ones is on accident.
Don't be too upset if you lose some gear, it can always be remade.
Extra tips
CLAIM YOUR COOPS - I usually set my farming to 60 so that I can steal from coops, most people do not claim their coops.
BUILD YOUR WALLS PROPERLY - Dig a deep trench on the tiles in front of your walls, this will severely limit people's ability to get over them.
LEAVE NO TREES - Seriously, deforest everything within short range of your walls. This will slow down any serious sieges.
DECOY BAGS - Leave bags around with decent stuff you don't need in them. Extra bits of chainmail, old tools, etc, as this will deter people from reaching your actual valuables.
DON'T FEED TROLLS - If they taunt you in-game, just ignore them.
Always remember that a naked enemy can be the most dangerous enemy. Keep your most valuable possessions on lock down in a warehouse.
Thank you for reading, I hope it helps.