How to improve one's memory ?

As far as I know practice does help (and it is also recommended to prevent Alzheimer disease).

Try this site for mind games. It can be both fun and productive :-) 

Or this one (which has free downloads of games) 

The brain disposes of any "unnecessary" information so it will be able to get new informations - the problem is that it refers to unused information as unnecessary. 

Information can be remembered for longer time if you process it more:
if you only hear something and not think about it, it will be lost, but if you think about it and try to connect other informations to it, you will remember it.

Within the processing procedure, you can try to connect the new information to knowledge you already know; you can build some logical story you can relate the information to, so when you'll need that information you automatically remember that story and that will trigger your memory of that information; you can make songs about the information;

Also, if you use the information in conversations or write it down or if you can do a physical action that is connected to the information, you will remember it better.

Use the information you want to keep, that is the realization.

there are many medicine that are made to be a memory enhancer try Gingco Biloba it is has a natural elements that help us to have a sharper mind.

It’s a common myth that we use only 10 percent of our brains. We actually use all of it. But just like your body, you can improve your
mental fitness. Use these strategies to increase your brain power and keep it healthy as you age.

Perfect your posture. Try solving a problem while slouching versus sitting upright and see how it impacts your mental clarity. Now sit up straight.

Use trapped downtime. Plan ahead with an Mp3 or iPod loaded with a good book or advice from a personal-development expert for when you’re stuck in
traffic, in line or in a waiting room.

Tell a good story. Sharing experiences in a compelling and fun way sharpens your mental recall.

Mix up your routine. Take a different route to work, or eat your salad after the main course. Changing your typical way of doing things tells your brain
to wake up and pay attention.

Write. Writing notes, poetry, stories or in a journal helps your memory, clarifies your thinking and engages your creativity.

source: http://www.vitalnutritionals.com/alternative-medicine/mental-fitness-for-brain/

Hey Oron,

I  know this is an old post but I have some insight that may help you in this. First off do not underestimate the physical (hardware) side. Get plenty of sleep and eat a healthy balanced diet. Fish and other omega 3 & 6 rich foods are vital as well as calcium. Iron to carry oxygen to your brain and proteins to to build and maintain brain synopsis. New scientist 12/12/09 has an interesting article on page 18 about protein's role in brain repair. Cut out alcohol and drugs which damage memory.

Then the mental (software) side.

Any activity that requires concentration and alertness will help so challenge yourself everyday, weather it be puzzles, chess, maths etc. I have a couple of techniques that can help with memorizing long lists and numbers. I use both depending on which I feel like at the time.

You can make a story from the list and then run it through in your head a few times. If you make each item big and vibrant in your head this will be easier.

Then there is the mental map technique. Think of a walking route you know well, I generally use the route from my house to work. Simply read through the list and imagine each item placed along the route, again make each item big, vibrant and easy to remember. The great thing about this method is you can remember it both backwards and forward!

With just a little practice you should have no trouble remembering up to 30 items.

This may take you some time but if you can think of an item for each number 0-9 and for a-z then you can use it for long numbers and initials.