Best ways to improve memory
Your best bet is to start looking on YouTube and the Internet for various memory methods used by card memorizers, magicians, and other stunt people.  I have used them extensively, and they work.  You can also look on Amazon for books.  Tony Buzan, Harry Lorraine, Dominc O'Brien. Also the book Moonwalking with Einstein.

Don't believe all the nonsense out there about your limited memory, or it takes years of practice, or you need special supplements.  I've met SEALs who used the simple techniques taught in the books to help them.  It worked for them.