A crash course in changing the world.
Don’t fight culture (If people cook by stirring their stews, they’re not going to use a solar oven, no matter what you do to market it. Make them a better stove instead.)\
I think this is a very good secret to have in mind because if you're helping anypeople in any way, if you try to change their culture, themn they could not like it and would have no idea how to use it. If you just give them the thing their using, but better, I think they would be very grateful with that instead of trying to make them use more technological things.