One of the best natural and historical way to do business is by involving in agriculture activities. The reason why I said that it is historical because it was done by our ancestor before they have any advance technology like us today. During that day, they do plantation for living to get their food supply. Nowadays vegetables and fruits had become money earner for farmers. So if you have unused land, you can start to plan about involving in agriculture as it has high demand by people. To sell thing, you need to have buyers. If you sell fruits and vegetables, there will sure be buyers because everybody needs them.
I suggest that you start organic vegetables and fruits plantation as it have high demand nowadays due to health awareness by citizens of the world. It sure will take some time but as the harvest season arrive, you will reap your rewards..