My oldest is adhd, which translates to he never stops moving! EVER! It also makes it hard to focus on his schooling. I found a few tricks over the last couple of years that makes it easier for him.
The first is a focus phrase. For him it was to take the bull by the horns. We taught him it meant to hold on for dear life and focus on the task at hand. This phrase was cool to him, because in Story of the World we had just learned about bull jumpers!
Another tip was a timer. It helped him to know he only had to work for xx minutes and then he could have a break.
Now that he is older, a list really helps him. I have to make it very specific-do 2 pages of math, study spelling words. But giving him that list and telling him work has to be done by this time or there is a consequence (no tv in the afternoon usually) works wonders on his focus!
When he was younger he did very little independent work. He hated handwriting so we did almost everything orally, or with me writing the answers except in handwriting practice. We also have used (as I remember) supplements-starting the morning with protein and caffeine seems to make a difference, and we also used flax oil.