At first, I was very lucky. My neighbors are very protective, and nobody would dare go on my property during daylight hours.
A while back, I got a call from my friend. He said "Hey, I'm here on your land, and a lady is staring at me! What should I do?" I told him he had better smile and wave, because she may start shooting!
Then the night prowler started coming. First, he stole some copper wire and a drill out of my tractor shed. Then he siphoned 40 gallons of diesel out of the dozer. I recently put a chain across my drive with a sign saying "Caution! Camera Surveillance!". I added a solar powered motion light, because I have no electricity on my land. So far, it's working.