The first thing to know when considering any major purchase is to be sure you are comfortable with who you are working with and ask plenty of questions. There are a lot of factors to weigh with a land purchase:
Does the land need to be cleared?
Has the property been surveyed, are there boundaries already marked?
Is there a deeded easement, utility easements or road frontage on the property?
Are there any environmental concerns or defects with the property?
Is the land you are looking to purchase zoned for commercial, residential or agricultural use?
If you plan to use the land for crops is the soil the correct profile and is irrigation possible?
Are there utility lines ran or wells for a water source?
How does the land lay? Sloping, valleys, elevation changes, etc.? Remember to consider drainage away from your property and drainage from any surrounding neighbors (you do not want too much standing water or flooding problems).
If you had to sell this property again in a year or two from when you purchase, would it be desirable to another potential buyer?
It is also a good idea to estimate what your annual property taxes would be on the land, and if you decide to build also consider taxes before you build and as you are developing plans with any builder (if that is your intent). Usually when owning a property outside of the city limits your taxes will be lower, but those estimates can be made for you with accurate property value assessments. There are a ton of different things to consider, it all depends on the intent of your purchase. Remember ask questions and find someone to work with that is knowledgeable, you are comfortable with and happy to work with you.
Purchasing a home or land is a life changing experience but, when done right, it can be a great asset down the road.