Here are ten quick tips on how to improve memory:
1. Use Repetition - Repeating to yourself the thing you want to remember may be simple, but it really does work. Repeat a phone number several times, for example, and you should remember it for a short while. This works even better if you "sing" it in your mind to engage other parts of the brain. To remember things long-term, repeat or review them several times upon learning them, then the next day, the day after that, the the next week and the week after that.
2. Write It Down - Let the paper remember for you. The point is to have use of the information later, and if that's more easily done by way of an "external memory device" like pen and paper, why not take advantage of these tools? Also, writing things down is another way to more strongly "fix" something in our minds.

3. Clear Your Mind - Sometimes to recall something you just need to relax and empty your mind of all the other stuff going on in there. Take three deep and slow breaths through your nose and relax your muscles. Pay attention to the air moving in and out of your nostrils. Afterward return to whatever it is you need to recall or work on.
4. Feed Your Brain - This means feeding your body of course. Your brain needs a lot of energy, and will generally function better if you eat some good proteins and complex carbohydrates. Trail mix, with nuts and dried fruit works well for some. Fish has been shown to immediately speed up brain function, as well as improve memory and other brain functions long-term improvement if eaten regularly. Also, the distraction caused by hunger can interfere with your concentration and ability to recall things.
5. Drink Enough Fluids - Dehydration is not always recognized, and can both distract you in ways that get in the way of clear thinking and memory, as well as more directly impacting the functioning of the brain. You can experiment to see if this is happening in your case. Just drink a glass of water and note whether your mind seems to work better.
6. Exercise - Physical exercise has been shown to improve brain function both immediately (after ten minutes on a treadmill, for example), and long term. The short-term effect is because of the immediate increase in blood flow and therefore oxygen to the brain. The long-term improvement in memory and other brain functions that come from regular exercise may also be due to the physical improvement of the brain and body that comes from this repeated increase in blood flow and oxygen.
7. Learn A Mnemonic Technique - There are many good memory techniques for remembering names, numbers, lists of things and more. A simple list of items can be "fixed" in your memory, for example, by linking them together in a crazy story that you visualize. You can find some of these techniques (as well as other memory tips) covered here on the website and in the Brainpower Newsletter.
8. Imagine The Use - If you think about how you will use information, you're more likely to remember it. For example if after learning a new algorithm in a math class you imagine using it during a test, you'll probably remember it better - particularly when taking a test. Imagine meeting someone again in the future and using his name, and you'll likely recall it when that does happen.
9. Avoid Toxins - Smoking is the obvious one here. Although it may actually help a person concentrate in the short-term, the damage smoking does may later hurt brain function in general, including memory. Many prescription drugs and of course illegal drugs can also have a negative effect.
10. Reduce Stress - When you're stressed, your body releases cortisol, which at high levels interferes with the part of the brain that handles recent memories. Chronic stress has even been shown to cause brain shrinkage. Meditate or do other self-work to learn how not to be stressed out. This may be the most important of these tips on how to improve memory, good not only for the brain but for your whole body and life experience.