I just finished reading Aaron Nelson's book The Harvard Medical School Guide to Achieving Optimal Memory and I wanted to share some key points. Research and experience have shown that the following lifestyle adjustments lead to better long term retention, and they won't cost you a penny!
1. Sleep. Research studies have demonstrated that 8 hours of sleep gives the hippocampus enough time to move short term memories into long term storage in the cortex. One study of college students showed that people with 8 hours sleep retained information the best 24 hours later and even a week later, while people with 4 hours retained it the least. 6 hours was in between.
2. Exercise. Cardiovascular workouts increase vascularization in the body and improve oxygen transport into the brain, which is thought to encourage new protein production and synapse growth.
3. Diet. Lower carb intake seems to be related to better hippocampus function. Try to stick to a low carb, low fat diet that is rich in omega-3, take plenty of vitamins, lean proteins like seafood, lots of vegetables. This all leads to enhanced protein production and better circulation which again helps with oxygenation of the brain.
4. Drugs. Minimize caffeine and alcohol, which both seem to affect memory.
5. Stress. Reduce stress factors in your life (more sleep and exercise will help). Meditation and prayer help. Stress response hormones seem to inhibit the hippocampus function.
6. Distractions. A key to retaining information is to be very focused. Turn off the computer, turn off vocal music, and try to focus for 50 minutes out of the hour on the task at hand. Then take a 10 minute break, walk around, stretch, clear your head.
Lastly, he mentioned various mnemonics techniques which are well known. He suggests associating information with different rooms in your house. Lately I have found that assigning a color to an idea somehow helps me to remember it. Use rhyming, music, turn the idea into a jingle or poem. There are lots more such techniques out there.
I hope this information is helpful to you, and I wish you best of luck with your studies!