One of the big challenges in working with children with autism is finding something they're willing to work for. Most children learn and grow because of social pressure, either pursuit of praise or avoiding shame. Neither of those motivations tend to work particularly well with children with autism (or at least, definitely not with my children).
My boys still do things for attention but its generally not enough to get them to stop doing something they're really enjoying (like running around shrieking during a movie) or start doing something they don't want to (like reading a book aloud). I have no control over their sensory preferences and escape is usually the last thing I want to encourage.
That leaves tangible motivators. This can be anything from a treat to getting computer time to (one of Alex's favourites) getting to ride on an elevator. (If I had an elevator at home, he'd be a lot more academically advanced right now. Or bored of it and I'd have to think of something else to use.)
But I've found there's a hidden trap. One would think: the more your kid wants it, the better a motivator it will be. But if the reward is too big, my kids get focused on the reward instead of the task. They try and rush through the task to get their promised reward and have very little tolerance for delays of having to do things right.
Too big a reward can actually become a deterrent to learning the lesson you're wanting to teach. Not intuitive, but true. It can also become a real challenge if your child doesn't meet the required standard to get the reward. Imagine how upset you'd be if someone promised you a million dollars to do something and then you couldn't do it. You wouldn't just be frustrated with failure, you'd be upset at missing out on the money.
So I've learned to ration out rewards. Small rewards for small steps and big rewards for bigger, but still achievable ones. And some things Alex really loves, he just gets to enjoy without having to work for it.