Two ways to go about this, broken window theory or make some friends.
I think we all know what the broken window theory is, don't allow even the slightest infringement, report all, prosecute all, don't allow anything to slide. Doesn't sound like many have had results with this without going through emotional drama that drains ones enjoyment of what they love.
You could make a friend of a couple of these people. I have chosen to do this on my place. I do not kick of trespassers. Found a guy illegally hunting turkeys and told him it was my place but I wouldn't be hunting turkey that year, could I hunt deer on his land? He was cordial and said his land was only big enough for him to hunt so he couldn't make the trade, never saw him again.
Find a couple of them and tell them they seem to be enjoying he place nicely and you can't be there all the time. If they help to keep people out, don't make any messes, assure the signs stay up, you'll let them do specified activities on the place. All you ask in return is the help monitoring it and perhaps some help with trail maintenance and some other small tasks. I have made many friends with this tact. This is more the Dale Carnegie method.
Broken window or Dale Carnegie, both different approaches but a similar ending if done right.
I just got a new pond, I made it twice because I aint so bright.