Here is the method I used to learn the alphabet in reverse. Using phoenetics, and a slightly re-adapted alphabet song, I was able to quickly and permanently download this info to my head. I could seriously be out drunk driving, get in a car crash, have amnesia, and still be able to recite the alphabet backwards during a sobriety test.
Most people learned the alphabet initially from the alphabet song. It is broken down into 8 sections. ABCD-EFG-HIJK-LMNOP-QRS-TUV-WX-YZ
Backwards, using the same 4-3-4-5-3-3-2-2 bars, it becomes:
ZYXW - VUT - SRQP - ONMLK - JIH - GFE - DC - BA
zikeswa - vhat - sirquip - onmilk - jih - gufeh - dic - bah
Practice singing that with the same melody as the alphabet song. Sing it once or twice to get a hang for it, then say the phoenetics aloud a couple times, then do the song again. The phoenetics are rather unique, and if you say them in a unique manner each time, you will easily remember them, and in turn, the letters in each bar will be easy for your brain to extrapolate. :hai: