Motivate yourself, the worse things are distraction. Imagin you are studying and and you decide to award yourself with ten minute worth of MSN time and you ended up having a 1 hour session. Set tasks on what you have to complete, give yourself breaks but dont get distracted.
Do some excercise to keep fit. Many people give up sports in their senior years, go and do some excercise, your concentration lasts longer. And you can take your anger out o what ever ball you are hitting.
If you are studying any science or mathematics make sure you wite up all the formlaes you need to know. Revise 24 hours after the lesson, then 1 week, then 3 weeks.
Use your time wisely, fis your best time to study and make sure you do it.
Do past questions^^
I am sure alot of people can add to this but good luck anyway.