I have a bit of land, I'll fill you guys in on some of the stuff I learned in acquiring, maintaining and developing it. My personal experience is in buying unimproved land and turning it into my home. I am not a farmer, a real estate man or a lawyer, nor an urbanite, an investor or a HOA dweller. I am a DIY homesteader.
Location. Good locations aren't cheap anymore. You aren't going to find 80 acres of nice flat land 20 minutes from your job for $1,000/acre. You will find expensive land or difficult and/or remote land.
Climate. Don't move to North Dakota as a Florida boy thinking you can just make it work. You need to know if you can handle the climate and its challenges. Take into account hazards such as being in a tornado or hail hot spot, hurricane zone, drought zone. These hazards will have a huge effect on your construction and lifestyle. Examples: it's a lot more expensive to build a house that will stand up to a tornado and you'll need a veritable bunker of a shelter, you'll have to dig a deeper well and take into account irrigation if you live in a drought zone, your insurance will be insane if you're in a hurricane zone. Etc. I've personally had both a tornado and hail on my land. If big hail ever happens where you are building, get at the very least a sturdy car port for all of your vehicles.
Topography and geology. You need to familiarize yourself with the topography of the entire area and its basic geology. You need to know where the highs and lows are, and have a decent idea what the soil and trees hide. You do not want to pick out some land, clear a spot to build a house, and find out it's downhill of something a mile away and now you've cleared yourself a nice little flood zone. Flood maps and zones are available but they are sometimes not granular or complete enough. Geology is massively important. Build in the wrong spot and you've turned your simple home well dig into something that costs tens of thousands of dollars because you have to pay someone to drill through hundreds of feet of hard rock. If you want to cut yourself a little airstrip you better pick something that has a nice flat area without many rocks. If you plan to farm you need to consult resources like the ones others have posted about in this thread already. Know where your local faults are, if you have any.
Utilities. Unimproved land means you're going to have to pay for an electric hookup. This will cost tens of thousands of dollars if you aren't already bordering some good distribution infrastructure and keeping a short run to your house. Underground is preferable from a safety, maintenance and reliability perspective, but costs more. You can feasibly DIY the wiring in your house with basic knowledge from books and code information, but not hookups. You can DIY the trenches and that's about it, you can't run your own cables or install your own splice and transformer boxes. The power company owns that and you will pay a handsome price for it. City water and sewer are arguably worse. You can DIY a septic system but you shouldn't because of the ramifications of it going wrong, your septic system has location concerns and interactions with your well all its own.
Defensibility. Chances are you won't be able to afford to fence in your whole property if it's anything more than a few acres, fencing is expensive to pay for and extremely time consuming to DIY. Consider what lies adjacent to your prospective property, you will have a lot of trespassers if you are adjacent to public land, or land that people treat as public due to an agreement with the owners. It is not fun to run into hunters, kids on dirt bikes, various flavors of retard, etc on your land and have to kick them off. If you're adjacent to a railroad you may have more bums using your land. If you're adjacent to an inner city you're going to wind up with people dumping.
Existing structures. A whole thread can be made about what you need to look out for with a house, this post isn't meant to be exhaustive so I'll focus on other structures. Barns are often unsound and demo is expensive, they are also less demanding from a code or safety perspective than a home. Many have dirt floors, you'll need one with a good concrete foundation if you're a car guy. Don't neglect the pump/wellhouse, it's important to keep your wellhead from freezing, shelter your pump from weathering, etc. It may need conversion from mechanical to electric if the installation is old, and will need a heat source if you're in the bitter cold. Power transmission lines and associated towers come with rights of way for the power company and present an added lightning hazard, and electrical interference issues if you are a HAM (many homestead types are). Inspect any structures closely. Pay an inspector who knows what they're looking for with inhabitable structures.
Roads/driveways. Here's something you can DIY entirely if you want. You can rent equipment or buy it cheap and broken if you fancy yourself the next diesel creek or Marty T (youtube channels somewhat relevant to this post, you can learn a bit from them). A cleared, leveled and graveled drive is perfectly usable for most cases but may present issues in the winter time, which you must take into account. If you love stupid cars like I do, you'll want to pave all the way up to the main road which is very expensive. I did this and screwed up the concrete in a section of it because I waited too long before starting it and getting screwed by weather. Removing the old concrete was ass.
Wildlife. You can run into issues if endangered wildlife resides upon your land. You need to be aware of your local wildlife from common to rare, from harmless to dangerous. Unless you are a psychopath, you will not want to harm vulnerable animals. If you are a psychopath, go live in a city and mess with bums and illegals, leave the animals alone.
Legal bullshit. You need to be sure of the borders, a survey is prudent. Familiarize yourself with the zoning, tax laws, and surrounding development plans of the area. In some places you can get homestead tax breaks, in others you can't and you will pay a steep tax bill if your area begins to develop and drives your property value up. You don't want to run afoul of zoning and development plans unless you are independently wealthy, and while you may get away with many technically illegal things in the boonies, if you're only in an up-and-coming area you may run into problems when the area begins to develop. Use an attorney to ensure that you do not run into deed issues or rights issues. Mineral, lumber, oil, etc rights can be an issue. If you buy a piece of land that has outstanding legal issues you are unaware of it can ruin your life.
I'm not an expert, I just have been through a lot of this on my own.
