First you need land. Then people who are willing to work it. Then knit them all together in some way, ie culturally/religiously/ethnically. The steps can be done out of order but it works smoothest in that format.

It's like Vlad said, only there's much more to it if you want to make it work. I'd be interested to know how you're coming along on trying to form a tribe. I'm interested in doing the same, only in the Southwest. What I mean about more to it is beyond the economics of finding and buying suitable land, you've got to have the skills to know how utilize what the land gives, and the social skills to cooperate and manage conflicts. Many a commune has come and gone. There are good books from people who're experienced in starting "intentional communities", and using consensus decision-making, and also many good books and training courses in learning primitive skills and more modern methods of home-steading. I would get to work learning these things first, and then finding the right people and place will hopefully come together in time. By pursuing your interests you're likely to find others who share them. Good luck!