Drive the neighborhood. Go at least a mile in either direction of the land, then try the side roads around it. Things to look for are homes that indicate drug problems.
When you walk the land, be sure to walk the boundries. You'd be suprised how often a neighbor will start to use somebody elses land for a dumping ground.
Crossing places along the fence will indicate tresspassers.
Look for signs of hunting on the land. Neighbors might feel they have a right to kill everything on your land since they've been doing it for years.
Are there any fourwheeler trails? Where do they start from?
Go to the land at different times of the day and differnent days of the week. Neighbors might love to shoot their guns all day long on Sunday, but if you only went there on a Saturday, you wouldn't know this.
Find out what utilities are available to the land. Also figure out what it will cost to bring them into the land. Water on the other side of the road might cost many thousands of dollars to get it under to your side.
Find out about every easment through the land or along the side of it. This could be very bad, or no big deal. Most power companies have easements along fencelines to trim trees from power lines. Standard stuff like that is normal. An neighbor with an easment to cross the land could be a nightmare. You need to know these things beforehand.
Mineral Rights are the right to whats under the surface of the ground. It could be anything from oil to coal. If you don't have them, then the person, or company that does, has the right to come onto the land, build a road where it wants, remove what's in the way, and drill wells, leave pumps and run heavy equipment back and forth whenever they want.
Always find out all information for yourself. Your realtor may, or may not know what they are talking about. Don't rely on there so called expertise.
Be sure to get comparable sales records for everything in the surrounding 10 miles and go back at least three years.
Never believe the reason for the sale. Don't even waste your breath asking. They are selling because the don't want the land anymore. Why they don't want it could be as simple as the want to live someplace else, or as bad as a local drug addict is breaking in and threatning everyone.
Be sure the price your paying is online with what you can get for it if you have to sell it much sooner then you imagined. Plans change, things happen. Nobody can predict the future, so have a plan for "just in case."