While ascending the scale (from the 6th to the 1st string) I use index, middle, ring and reverse it while descending (ring, middle and index finger).
Left Hand
It depends on what notes I need to play. Let's say I wanna play 2nd - 3rd -5th fret I'll use index, middle and pinky. If I have to pay 2nd - 4th - 5th fret I'll use index - ring - pinky.
Check out Christopher Schlegel, Bobby Howe and Lisa McCormick's lessons and you'll get some very good tricks on fingerpicking.