Read FIVE MORE pages. Finish FIVE MORE math problems. Work FIVE MORE minutes.
Just as athletes build physical stamina by pushing past the point of exhaustion, you can build mental stamina by pushing past the point of frustration.
Just as runners get their second wind by not giving up when their body initially protests, you can get your "second mind" by not giving up when your willpower initially protests.

Source: tips

You may try this simple mudra practice Gyan Mudra (Mudra of Knowledge): This hand mudra requires you to touch the tip of your thumb to the tip of your index finger, with the other three fingers stretched out. This hand mudra helps enhance your knowledge. The tip of the thumb connects to the centers of the pituitary and endocrine glands. When we press these centers with our index finger, the two glands get stimulated and work actively to increase and retain knowledge. There is no particular time duration to practice this hand mudra. It can be done sitting, standing or lying on bed at whatever time and place you wish.
Benefits:
- Increases memory power and sharpens the brain
- Enhances concentration and prevents Insomnia
- Regular practice ensures the cure of psychological disorders such as hysteria, anger, depression and other mental problems.

I wud suggest every student to wake up early in the morning by 4.00/4.30 and have a session of Pranayams like kapalbhathi, Anulom Vilom, Bhramari, udgeet etc.; this will provide comple energy fior the whole day and much concentration on their study without worrying abt anything happening around them. Also make it a practise to go to bed early say around 9.30/10.00 P.M. Do and achieve. Success is yours. Vande Mataram

Put some tag some where like if you want go for walk ,see n remember,