Try writing down key concepts and a short explanation.
Also, make sure you have enough vitamins in your body, and you have something to drink, and you're not hungry or too full. A healthy body is key to a healthy mind.
Location is important to me personally. I can't study at home, because I'm tempted to go online or sleep, or do something else. I go to the open-24-hours Starbucks by my house, and sit in the big comfy chairs, and study there. The noise is constant, so you're not really distracted by it. There's bathrooms, and I can get water for free when I'm thirsty, or somethin else to get my energy up if I'm tired. Great stuff.
