I think that breaking the studies into smaller parts will make the work more easy for our juniors like reading one chapter at a time rather then a number of chapters together!!!
To my mind the primary duty of a teacher in developing concentration lies in his art of presenting the subject in an attractive and exciting way and once he or she succeeds it is not 50% but 90% of the battle is won!
Studying in a calm and quiet atmosphere will increase concentration.If children studies in room and parents watch TV in next room it will not work at all.
Physical surroundings are ,no doubt, important but what is more important is level of interest that a student takes in his or her subject.Here the role of parents and teachers is very vital!