If your brain isn't cool.

Then you are not either. Brains are a very predictable organ. When they are cool they work very well. When they are not cool they don't. This is why. Your brain represents about seven per cent of your body weight. Your brain, however, uses about seventeen per cent of the oxygen that you breathe in. That is a lot. The reason is that our brains require a lot of oxygen to stay cool. The oxygen is supplied to our brain by our blood circulation. This is accomplished by our big blood pump, the heart. As you can tell the brain is a very jealous organ. It demands a lot of the heart and lungs. This is, as I've said, because it needs to run at an optimum temperature. That temperature is approximately 98.6 degrees Fahrenheit. A steady flow of oxygenated blood effectively keeps our brains cool. The best way to keep our brains cool is to breathe. Deeply and regularly. We don't think about breathing much because it is an automatic process. Still it is wise to pause occasionally, especially while studying, and breathe deeply. Keeps your brain cool. And when your brain is cool it works.

Planet College Advisory: Highlighting

Ever found yourself pawing diligently through the used books stacks hoping to snag an affordable copy of a text book you need? Uh-oh. OK, here's one and it's almost cheap. Cool. Until you open it and find it has been so highlighted that it is almost unreadable. Highlighting when over done, and it nearly always is, is distracting. Distracting to the point of uselessness.
Here's a Planet College advisory. Don't highlight your text book. Instead use this simple system. Study with a number Two Pencil ain hand. When you come across a valuable, noteworthy or useful fact carefully place one check mark in the margin of the book. Place it along side of the paragraph containing the fact. With this method you can develop a system based on checks. One check for rather important, two checks for very important, three checks for extremely important. If the passage contains extensive information you may also consider underling important parts with your Number Two pencil. When you go back to review the material you will be able to quickly determine the relative importance of the material you are reviewing.
This method has another advantage. It is much easier to clean up a used textbook for re-sale when all it has is pencil markings.