Please give me some tips on how to enhance the memory?

Memory definately suffers from lack of sleep. However I like the ancient greek method of learning massive amounts of information. They learned pages of texts in different rooms in their house. They start at the front door with the first page, or paragraph or whatever and memorise that and associate that idea with the front door. Then they move to the next room, say the living room, and learn the next idea and so on.

Then when you have to recall the ideas in order you imagine yourself walking through your house (which you obviously know intimately) and the ideas associated with each room will come out. Its a kind of compartmentalisation. You sort of trick your brain into remembering everything by associating each small concept with something else you know. It gives you a key to pull out the memory. "now columbus landing was the bathroom" - walk through the house in your mind to the bathroom and recall the facts you memorised associated with that room. Your brain will track through everything you memorised in each room and recall the fact associated with the bathroom. Its very cool when it works. Good luck.