#'s
------
Father
Charles
Goes
Down
And
Ends
Battle
b's
-----
Battle
Ends
And
Down
Goes
Charles
Father
It may seem a little juvenile, but it works really well. If you want you could always come up with your own saying for this. To get the notes of a key, you then need to remember the number of sharps or flats in a specific key. I find a the cycle of fifths (specifically the circular diagram) works well for this.
