I echo what Becky said, especially about the short-term positive reinforcement and communication with the parents. Goals need to be achievable by the student. Without a measure of success they will give up. Parents do need to be informed about what is happening in your class, both the good and the bad. Another person to keep informed is your school principal or administrator.
One thing to consider is seating arrangement. I have found that for me to give the proper attention to a “needy” child, they must sit close to me. Otherwise, they don’t ping my radar as easily. Front row seats are usually best for the child who has difficulty paying attention. There is less to distract him and you notice when he gets lost quicker. However, sometimes a child becomes the distraction in the front row and needs a back corner instead. If this is the case, sometimes you need to teach from the back of the room.
I have heard of classrooms with a mini trampoline in a back corner. This could be used as a reward for positive actions or as an energy release.
Learn to know your student. I once had a student who never looked like he was with me. He could be staring out the window or watching a fly buzz overhead. Yet he usually knew what we were talking about. However, most of the time you will know if they are engaged or not.
Appreciate your student for who he is. That young man who finds it so difficult to sit still and focus on his school work may be his dad’s best helper at home. That doesn’t mean you don’t look for ways to help him be successful in school also but if you realize that he has potential it can help your frustration level.