Don't leave them up during the weekend. Or buy a good one that sends pics to your phone and put a tracking chip in it so you can get it back after its stolen. I saw a trail cam on public land once and it had a little sign under it that said it was a wildlife research project being done by a local college.
There was a product at ATA show that allowed you to mount the camera with a special tool that made it very difficult to steal and you could mount it up high from the ground. I don’t recall the name but they mentioned it on wired to hunt podcast.
Take a couple of portable climbing sticks and place it high out of reach. The majority of sleezy dirtbags won't go through the effort to snag it. The guys who do have the means and work hard normally don't have the time or interest. Also, keep your reconyx on private land.
I use an old beat up camera or two - and I I put a note in it that says "please don't take my camera, it only kind of works and its all I have. If your picture was taken I do not care, I will delete it" so far that has worked. I don't put them on main trails or obvious places - most times when I do get peoples pictures - they don't notice it. I tuck them into tree crotches, but don't go out of my way to hide them.
They will take it or destroy it if they want to, no matter what you do to secure it. CamLockBox lag bolted into a tree with a Masterlock on it is about the best you can do. Hope nobody finds it and don't use an expensive cam.