Huda, for a strong memory eat walnuts:) they say it helps and it's really tasty (,")

Once I heard that memorising phone numbers and not relying on your phone memory helps a lot in making your memory stronger.

I watched one vedio stating that the things or scenes that is more unnormal or more bizarre, the better memory about these things you will get. 

I do think it is right, as we could think about our own exprience about memories of bizarre things. Obviously, some horrible or nervious or bizarre scenes haunt us, and it is very difficult to get rid of them. Also, absurd words such as some moives lines or radicious scenes from comedy moives are very easy to remmember. Maybe you could by using these knowledge to help you build a persistent memory.

I fully agree with the comments above -and of I like the topic too. 

-I quote phisical ( training, meditation, sleep, food). 

-plus 

I don't know what do you want to memorize and for how long time do you want to recall your information. In this sense I'll write you down something that  should work fine as post it for your brain. 

This won't be useful if you want to memorize numbers, chinese characters or entire sentences like for law Codes.

-Think of the mind as a room, what is in your room? how is you room, messy or neat? Can you see how you left your room before you went out?

You could try to associate the things that are in your " room" with the information you need to memorize. This could work good with concepts. 

You could even use sports instead.

The ball can be a dispute between two factions, the number of players the arguments. Maybe assigned on the players you like and remember.

You can also recall the  information trough events, it's more likely to remembers sense related information. (Your birthday date, someone or something you hate, your favorite dish or smell, a kiss , once you got hurt phisically, a color,)

Training. More you use your brain, better results the brain gives you.

Meaning. Just use the information in important and interesting way to you.

Learning new things like different languages can help yr memory stay strong and active.if u wanna keep yr brain strong u have to feed it,and what's its food?a healthy diet,exercising and new information