The graph shown here is called "The Ebbinghaus Forgetting Curve". It indicates the rate at which human beings forget new information. As you can see, we forget almost 70% of what we learn within 24 hours. Even in the first 1 hour, you’ll forget more than half of what you've learned.
Solution to this problem of forgetfulness, is regular revising and practice of the knowledge and skills over a period of time.
Here are some techniques to increase your memory.
1. Regular revision – Recall what you have learned on a regular basis. The hour/day/week/month model is one. Ebbinghaus Studies also found that a stable long-term memory is established only after an average of 7 repetitions. That means you need to review a same lesson several times before you can effectively retain it in memory.
Let's say on day 1 you learned a lesson. They should be reviewed once to twice again on the same day, once more on the second day, once more in a week, once more in two weeks, and again in a month. Research suggests that the spacing is different for individuals. Recent research has shown that rehearsal just prior to sleep is a powerful technique.
2. Take notes and prepare a short note – Write up the lesson, in your own words with diagrams, and prepare a summary or short note of the lesson. This can result in dramatic increases in learning (20-30%). Then re-read a few times afterwords.
3. Repetition – Before starting a new study session, repeat (not in parrot fashion) the what you've studied previously. Take five or ten minutes at the start to revise the previous content.
4. Practice – Do questions, past papers after the course. This prevents reliance on short-term memory and gives you a chance to develop long term knowledge and skills.