Let me share what i know about keeping your stuff safe in the game because its actually pretty straightforward once you know the basics. The tool cupboard (tc) is going to be your best friend here, and you'll want to tuck it away deep in your base behind multiple walls, making sure its always locked and filled with resources to prevent decay. Something interesting to keep in mind is using railings or half walls behind your doors, which stops people from trying to trap you inside.

Your entrance setup is really important and single doors are basically asking for trouble so definitely go with airlocks instead. Good to know: think about building what players call a tank anti grief setup, which basically means reinforcing your core with multiple tcs to make it super annoying for raiders to completely wreck your base.

Playing on servers with active admins makes a huge difference, and if you spot someone causing trouble just grab some screenshots and report them. Building in quieter areas away from the action helps avoid unwanted attention, and its worth keeping some extra building materials handy just in case you need quick repairs. Moderated servers usually have pretty clear rules about griefing, and some even use whitelists to keep the troublemakers out completely.

Maybe interesting external tcs placed strategically around your base can prevent enemies from building nearby, which is super helpful when youre trying to keep your area secure. Just remember to keep checking for any signs of tampering and try not to start drama in chat that might make you a target.