Distractions compete for your mind's attention. External distractions, such as loud noises or interesting scenery, or internal distractions, such as nagging worries or vivid daydreams, divert your attention and destroy your concentration. The proper environment is a place you use only for studying and use consistently. The area should be relatively free of visual distractions and noise, including music. The area should be brightly and evenly lit to discourage fatigue and prevent eyestrain.
Good lights head the list of equipment that encourages concentration.
A comfortable chair is important as well. A bookstand can free your hands and keep your textbook in a position that encourages active, focused thinking. Well-stocked and accessible supplies help you keep your mind on your work. A concentration scoresheet is a tally of the times when your concentration is broken. To keep score, put a checkmark on a sheet of paper each time you realize you are no longer concentrating.