If you do this regularly your recall of the material will increase significantly. Avoid scheduling marathon study sessions. If you must study in long sessions, take a short break every hour, work on several subjects, and avoid studying similar subjects back to back. Setting specific study goals for each block of time will help you focus and concentrate better. Be aware of your best time of day.
Many people learn best in the daylight hours.
Observe yourself, and if this is true for you, schedule study time for your most difficult courses during the day. Use a regular study area. This will help you get down to studying faster because you are able to focus more quickly. Use a library. Libraries are designed for learning.