I remember a conversation I had about someone's brother, who quit studying guitar because his teacher made him do scales. The sister shook her head as if to say what a shame it was that the teacher had bored her brother on such trivia. It’s too bad for the brother. The effort spent in learning scales can put you in a different league as a musician. Unfortunately too many teachers try to teach scales by having their students memorize by rote in the form of fingerings. Try figuring it out and really understanding it in your head instead. You’ll truly know the keys you play in if you just sit down and calculate the scales by yourself, preferably without a book. Here are suggestions to get you going:
The first thing you need to know is a circle of fifths. You can find useful descriptions and aids online; I like the one by Catherine Schmidt-Jones as seen here and posted on Connexions, but look for one that suits your style of learning. The circle of fifths is cut into twelve equal pie shapes that are used to demonstrate the proximity among keys. It’s called fifths because each pie piece represents five notes. This is a useful learning tool, but I don’t rely on it in practice. Instead I find the best way to think about the sharps or flats of scales is simply to count on your fingers.
Try this example using the circle to get you going… Consider your thumb to be number one; for this example we’ll call that C (the scale of C major is a natural starting point because it has no sharps or flats). Count up five notes on your fingers starting with your thumb, or CDEFG. If you look on the circle of fifths, you’ll find that one pie piece clockwise (the direction for sharps) from C is G. Why? Because a fifth above C major is G major. That’s the key that has one sharp. The note that is sharp is actually the fourth tone, or the note right before the name of the key. In other words G major has one sharp and that is F. To find what has two sharps, start with G as your thumb and count up a fifth, or GABCD. Now you know D major has two sharps: the F sharp we already had, and the C sharp that we’re adding. You can continue this way going up keys and adding sharps, bearing in mind that when you get up to six sharps, which is F sharp major, that you have to include the sharps in the name of the key.
Once you’ve figured it out in your head, you can remember the sharp keys by using the mnemonic device “Go Down And Eat Breakfast,” because the keys with sharps are GDAEB. Another way of looking at what we just counted is that if you want to know what key you are in, just look at the last sharp you see and go up a half step.
Each major key has a relative minor (the darker side of the scales). The relative minors have the same key signature as the major, so the one that shares C major on the pie slice is A minor. The only difference between them is that A minor starts a little lower and ends a little lower. All you have to do to find the relative minor keys is go down a minor third. A minor third is only a whole step and a half step, three frets on a guitar. In C major you go down CBA. For another example: G major has one sharp (F sharp) and so does E minor. If you go down a third from G, which is G F# E, you have E minor. Now if you get up to A major, you’ll find that the relative minor is actually F sharp minor, because F sharp is in the key signature (you know, A has three sharps F, C, G).
You can use a similar technique to sort out the flats of the circle of fifths going in the counter-clockwise direction.
After you’ve figured out how scales work, I recommend that you get a copy of Aaron Shearer’s supplement three, the scale book. Don’t use this book as a method book; use it as an exercise book. It’s a sort of barbell for guitarists. Although I’ve spent many long hours in this book developing my speed and accuracy, I never really learned how scales work from it. The best thing to do is to understand scales, altered scales and modes to the point where you could write a scale explanation yourself.