First, I would have the student tell me what they want to learn and why they wish to learn it. If it's studying for a test, I will make them as well versed in the "big picture" as possible in the amount of time available, instead of getting caught up on every detail. If it's for general studies, I would find the student's weaknesses and give him/her the answers he/she needs to fix the toughest problems, and I'd put the student in a position where he/she could solve more future problems without assistance, because the student would know how to work it out alone.

My favorite strategy is explaining to a student how to solve a problem, and as soon as they start to get it, have the student explain it right back to me. This keeps information in everyone's heads so much more effectively, especially when dealing with individuals who have ADD or ADHD. Then I'll assign the student a task: the next time he/she learns something in class, take 5-10 minutes to explain it to someone he/she knows, and tell me the results.

A student will only be motivated if the individual feels like what he/she is learning will benefit him/herself. If the student doesn't seem enthusiastic, I'll ask him/her what the reason for these studies are. When the student has to come up with a tangible answer, it brings a whole new meaning to whatever subject is at hand.