Establish goals and work towards it
Stick to the goals, tweaking minute changes only according to situations that arise at various points of time.
Start off with a small time block say 25 minutes. Focus and do not deviate in that time. Give a 5-minute break and then study again for the next 25 minutes again. You can increase these time blocks as you go on through your semester.
TO GET HIGHER GRADES
Give more of your time and attention to weak areas and you find that your exam grades will automatically move up.
Practice previous year papers
Attempting past papers is akin to taking an exam. find a pattern in the previous papers which could help you predict what exam paper you will be getting.