When I first got married, years ago, I thought that I could change my husband's picky eating habits just by introducing him to the foods he said he hated. I was wrong. One night, I fried some green tomatoes for supper and when he came in that night, he said, something really smells good. He didn't see the green tomatoes, so when we sat down I told him to close his eyes and I had a surprise for him that I just knew he was going to love. He said it better not be liver or something...no chance of that, I hate liver myself. I cut a bite of the fried green tomato and put it in his mouth and he bit into it and if you could have seen his face! He spit and gagged and carried on like I had poisoned him. If he had swallowed it, I just know he would have had to have gone to the hospital and had his stomach pumped or something. I should have known that someone who doesn't even eat ripe tomatoes was probably not going to to eat green ones.
When fried green tomatoes became such a talked about southern food, mainly because of the movie with the same name, people in the south found it sort of funny. All of these Hollywood types trying them for the first time, people cooking them on food shows and talk shows, it just seemed sort of bizarre to us. Fried green tomatoes, originally, were a food basically of poor country folks who more than likely breaded and fried just about anything to feel like they had meat and something filling to eat. They are much like so many foods we eat in the south, they came about because people took what they had available and made the best of it. A talent that more people are going to have to develop to get by in the future more than likely.
Just like cornbread, fried chicken and sweet tea, each southern cook probably fries green tomatoes a different way to some degree. Some use corn meal, some use flour, some use a mixture of both. Some fry in oil, some in bacon drippings, some in shortening. Some dip in milk, some in buttermilk, some in an egg wash...on and on.
Here is what I use:
2-3 medium to large size green tomatoes
2 cups buttermilk
2 cups cornmeal
1/2 cup flour (plain or self rising, doesn't matter)
salt
pepper
Cajun seasoning (optional)
oil for frying (I use Canola)
1 tsp. bacon drippings (optional)
Slice the tomatoes in thick slices, not too thick, about 1/4 inch thick. Place in a bowl and pour the buttermilk over them. Let them sit in the buttermilk for 15 -20 minutes. 
Mix the cornmeal and flour in a shallow dish or pie plate and dredge the tomato slices a couple at time in the mixture. Turn them over and pat the cornmeal mixture into them well. 
Pour about an inch of oil in a skillet and heat to around 350 degrees or until it is sizzling. Make sure your oil is hot enough (but not too hot) or the tomatoes will be greasy and the batter may not stay on. Drop a little of the cornmeal mixture in the oil and it should sizzle. Leave room in the pan to turn the slices. Some people fry their green tomatoes in bacon drippings and while that sure does taste good, it's probably not really all that healthy. I get the same flavor by using Canola oil and just dropping about a teaspoon of bacon drippings in it. It really does enhance the flavor without being pure bacon grease.
Sprinkle each slice with a little salt, black pepper, and some Cajun seasoning, which is optional. It gives them a little spiciness, but if you don't like spicy just leave it off. Only turn once or twice while cooking or they will fall apart. 
Remove to a paper towel lined plate and serve immediately.
