Hello, all posts are helpful so far and there is nothing wrong with any previous suggestions. Just thought I would add my couple of pennies.
btw - before anyone laughs
- this is a proven and tested method for remembering info - there's even an annual world championship for Memory Experts who implement such sytems. I am not an expert but I am competent in using and developing such sytems. I use them all the time and they really do work.
My record for memorising a deck of cards is 42.37 secs using a slightly more complex but similar system
So here we go -
An Introduction to using Photgraphic Memory Techniques.
An alternative (odd) way to visualise X Y Z in your head. 
X - could look like "A Cross" so it goes across (left and right)
Y - could look like someone standing with both arms in the air and doing a starjump. (up and down)
Z - could look like a zig-zag path which you walk back and forth on (front and behind)
You can use whatever images that you want, the images I used are just the ones I used.
So now make a silly image in your head for each one - with you on a cross, you doing starjumps, you zig-zagging down a path.
Imagine the cross bending over far left then far right, bending to beat of the chorus of "Always look on the bright side of life". It's from "Life of Brian" film by Monty Python.
Imagine your doing the starjumps on a trampoline and bouncing up and down into space. Also make your arms like Mr Tickle when you do the star-jumps.
Imagine running back and forth the zig-zag path in a frantic race against a giant tortoise and a giant hare.
As silly, stupid and bizarre as this post may read, it's for those 3 reasons that your brain will remember them. The more silly, stupid or bizarre the image, the more the brain will try to make it link to other stuff in your head that you already know.
Just make sure you amplify or exagerate the XYZ mental images and directional movement bits so they stand out. Your brain will do the rest of the work
When you have done this, when your are working on something and need to use XYZ, make the mental picture you linked to the relevant letter and your brain will playback the bizzare sequence you made with it. Something like that anyway.......
As I said earlier though, the previous posts explain XYZ, I just like remembering things this way - it's fun!
