How do u remember what sharps and flats are in a given major or minor key?

[joe f]

So lets say you are sitting at the piano and you want to play B flat minor. How would u quickly remember which notes must be sharp or flat to create this scale? I want to be able to do this with all the keys A thru G sharp for major and minor. I dont want a way to remember what key a key signature is i want it the other way around.