That's a pretty broad question, but here are a few thoughts:

1. Realize financing can be challenging. A lot of banks either won't lend on something not hooked to the electric grid or are going to want a higher than standard interest rate due to the risk. Even more so if you're trying to secure a construction loan to build it yourself. Also, don't expect you're going to be able to sell such a property to recover your investment. There was an amazing offgrid place near me that was on the market for over a year and sold for less than half the asking price. Most people aren't willing to deal with the challenges of such a setup and the number of buyers and the ultimate price reflect that.
2. Consider your access to the property carefully against your plans. 3 miles off the county road down an old logging trail sounds awesome until the concrete people demand you clear them a 14 foot wide path clear 14 feet into the air and fix up 150 feet of muddy low lying area. Or until the first winter storm and now you get to try and plow your way out (I don't bother with that, I have a snowmobile and a garage right on the town road).
3. Consider where you're going to locate solar panels and just how far from the trees you need to be so they aren't shaded. Consider how tall the trees are going to be in 25 years. Removing a couple acres of trees can get expensive.
4. The further from the city you are the fewer choices you have in contractors and the less days of the week they seem to work. Expect everything to take longer than it would in the city and realize an early snow, or an early freeze with a snow and a warmup, can prevent trucks from accessing your site. Realize in freezing places there are weight restrictions in the spring when things thaw that can close roads to heavy equipment for weeks.
5. Everything is a tradeoff between cost and effort. If you can't fix small engines or do other routine repairs expect to be without critical services and equipment at inconvenient times while you try and find someone else to come out and do it for you.
6. Make sure you check to see how deep wells in your area are running and if the water quality is good, because those problems can cost thousands and thousands of dollars to remedy and you do not want to have to haul water. I hauled for my first week when I first started out and it was a pain even though I had a 276 gallon tote and a nearby neighbor that let me use his outdoor spigot.
7. How are you going to access the Internet? Starlink satellite is what I use, but realize you'll need to have a large clear area to the north or a high point to mount it to clear the trees. I could not rely on 4G service where I am due to fluctuating bandwidth and how much of it I use.
8. Know your limits and what you're really willing to do long term, otherwise you can end up just trading one set of annoyances in the city for a different set off grid. Depending how you do things there can be a lot of time spent on chores and other activities just to sustain things.

Rural life involves a lot more driving a lot longer distances for things and the recreational opportunities aren't generally there like you might be used to. Stupid things like getting a package delivered can become a hassle if there isn't direct access to your home. I'm over 3 miles from where my packages get delivered and the only reason that is even possible is because I built a small garage off the town road, otherwise I'd have to shell our $10 a month for a Post office box and drive there during business hours (mine is only open 6 hours a day with a huge two hour gap around lunchtime).

Don't be married to romantic notions like raising your own animals and food unless those activities bring you joy. To me they're just more work which is the opposite of what I'm going for. Small scale agriculture and animals are a ton of work and in most cases the economics aren't there. Spending $1 a week on chicken feed for 6 eggs is already a losing proposition before you factor in your time and all the other work it creates.

If you have a wood stove realize you're going to be carrying thousands of pounds of wood inside and you'll be going out every day or two into whatever temperature weather to get more. Felling and cutting and splitting take a ton of time.

Same with having an outhouse to save putting in a $10,000 septic system. It's great until you have to go at 2 am and it's raining outside.

Hopefully that saves you some hassle.