Key Signatures can be troublesome, and very annoying- they're very tiny and unnoticeable compared to the big music score, mess up the whole song if you don't play them, and when you think you've got them right, a natural is thrown in and gets you all off-balance.
Here's two VITAL tips to remember key signatures: The sharps (in order) are: F, C, G, D, A, E, B.
You can remember this key signature by the mnemonic: Father Charles Goes Down And Ends Battle.
A tiny bit of grammatical error, but if you learn this, you will learn how to remember the flats at the same time.
The flats (in order) are: B, E, A, D, G, C, F.
You can remember this key signature easily because the first four flats spell BEAD and the flats are just the sharps turned the other way around.
You can also remember them by the same mnemonic, only swapped backwards: Battle Ends And Down Goes Charles' Father.
Many people teach two different mnemonics for the flats and sharps- I like to keep it simple and just swap one mnemonic backwards and forwards.
If you really don't like these mnemonics (or have something against Charles' Father) then here are some more: - FCGDAEB: Fat Cats Go Down Alleys Eating Birds - FCGDAEB: Fat Cows Go Down And Eat Buttercups - BEADGCF: BEADs are Good, Cool Fun - BEADGCF: BEADS (at) Grand Central East Hopefully this has been informational to you, and remembering key signatures are very easy now.
Good luck on your music journey!