I got a few ways to help me concentrate.
1) Go Macs, buy a large green tea (healthier =D), and start
reading. Drink slowly, and just study.
2) same as above, but I go Cafe gailee in the National Library,
with a nice coffee.
3) Same as above, but I go KFC.
4) Sometimes I find studying in the MRT or BUS more effective, but
I don't know why. I've heard of pple (of cuz with MRT pass) taking
a train from Pasir Ris to Boon Lay and back just to revise their
work on the trains.
5) Sometimes I just sit in front of the TV. This is a slower way of
doing work, but it helps me last longer overall and thus more work
done. But this is not to be attempted by people who cannot
multi-task.
6) Make your room more comfortable for study. Make sure the
arrangement of furnitures and the colour combination don't make you
feel sleepy. On your air con/fan and sit down with a cold and nice
drink.