Do you teach them how to diagram a sentence, or do you teach them how to write? Do you teach them dates and periods, or do you teach them things that they care about? Humans need a constant to use as a reference point.
There is only one way to make them learn. You have to find out what they are passionate about, and then find a way to link their passion to the relevant things that they need to learn.
Chances are, the fellow who wants to rule the world won't have a lot of interest in hearing about the love affairs of some ancient King; but start talking to him about dictators and panzers, and he'll probably perk right up.
Naturally, most of your students - like most people - will go through class as they go through life; without any strong drive. You can't help them, so it is best just to let them float along. They will eventually find places in the lower tiers of society and be content to play their parts there.
Your duty is to the few, possibly even the one - if any - who are actually extra ordinary. You need to find the ones that obviously find life interesting, and make their lives even more interesting.
A person who reads one page and remembers everything on it for their whole life is much more knowledgeable than the person who reads all the text of ten volumes and remembers none of it in future years.
I never went to formal school, and I am probably almost young enough to be one of your students. If it is any proof of my point however, I'm a fluent writer and know more about history than most; and that isn't because of what somebody taught me. It is because I retained the things that really interested me in a personal way.
If you have never watched the film
"Goodbye Mr. Chips", you should do so. I am sure that you would find it to be relevant and encouraging. Good luck.
