Circle of Fifths

The circle of fifths gives you a system that organizes the keys for you. The circle of fifths helps you to learn the corresponding key signatures from majors to minors and vice versa. It's called the circle of fifths because every note is a perfect fifth apart from the next. The outer ring of capital letter are the major scales. The ring on the insides of lower case letters are the minor scales. Minor scales are all represented as lower case letters. The middle ring is the number of flats or sharps each scale has.
For example, between C to G is five notes. C-D-E-F-G.
The circle of fifths is a life saver.