Fingering Principles	Piano Pages   William Wieland
Finger your music. You will ultimately save learning time.
Write as few finger numbers as possible—only when the hand shifts position. Write all left hand finger numbers below the staff and all right hand finger numbers above the staff. Usually assign one finger per letter or one finger per key. Use as few hand shifts as possible. Short fingers (thumb & pinky) usually play white keys. Black keys are usually played by long fingers (2, 3, & 4). Use the weakest finger (ring finger) the least.
The major scales follow these principles. Now you can determine fingerings for natural minor scales, melodic minor scales, modes and, above all, real music.