Everyone knows that C major has no sharps or flats, right? That's the easy one--just remember it.
The memory device for major keys with sharps works like this: to write an A, you use 3 penstrokes. A major has 3 sharps. D takes 2 penstrokes and has 2 sharps. Here's a chart to help you remember:
A-3
B-5
C sharp-7 (use 3 sides on a C, like a square missing one side)
D-2
E-4
F sharp-6 (use a lowercase "f")
G-1
For major keys with flats, remember the phrase "Battle Ends And Down Goes Charles' Father."
It tells you the order of flats. If you see the key signature below, which has 2 flats, you know that the second flat is E flat. Go back one and you will get the name of that major key.

Did you get B flat? If you did, great. If you didn't, reread that last part until you understand it.
This principle can be applied to any major key with flats. Go to the last flat, then backtrack one to find the key! Once you catch on, it can really be a helpful way to remember major keys.
The minor keys are slightly more complicated, but as long as you can read treble or bass clef and you know the musical alphabet, you'll be fine.
As you may already know, each major key has a relative minor key. They share a key signature, so if you know one, you can easily find the other. Now that you know B flat major above, let's find its relative minor.
Start on B flat and go six steps up its major scale (B, C, D, E, F, G). Don't worry about accidentals right now. The sixth step of this scale is G, and the key signature says G is natural. So the relative minor to B flat major is G minor. Its key signature looks like this:
Make sure to practice these tricks and share them with others if they work for you. Email me at agrishner21@gmail.com with questions. I hope this helps!


