If you're composing music, you generally use one of the seven main types of musical scales, or modes, generally referred to as Greek scales. Each one consists of eight notes, combining whole and half steps in slightly different combinations to produce different feelings in the listener. The following list shows these Greek scales:
Ionian (the major scale): W(hole step), W, H(alf step), W, W, W, H
Dorian: W, H, W, W, W, H, W
Phrygian: H, W, W, W, H, W, W
Lydian: W, W, W, H, W, W, H
Mixolydian: W, W, H, W, W, H, W
Aeolian (the minor scale): W, H, W, W, H, W, W
Locrian: H, W, W, H, W, W, W