Knowing proper left-hand position for bass guitar will make fretting chords and fingering strings simpler because the left hand will be more comfortable. By keeping it loose and relaxed, you'll be able to fret the strings with the least amount of effort. The proper position also enables you to play at great speed and with great accuracy.
You want your left hand to cover one fret per finger without causing any undue stress in your hand. This spacing will set up your hand to execute almost any musical figure without shifting. When you do have to shift, a move of one fret in either direction usually suffices.
Stretch your left arm out in front of you.
Keep your wrist and hand limp.
Without changing the angle on your wrist, turn your hand over so that your palm faces up and your fingers are slightly curved.
Position your thumb so that it faces your index finger (or the area between your index and middle fingers).
Bring your elbow in to the side of your rib cage (without moving your hand) until the bass guitar's neck is in the palm of your hand.
Don’t close your hand yet!
Place the tip of your thumb on the middle of the back of the neck.
Make sure that your fingertips are pointing upward.
Gently spread your fingers onto the strings, with each finger close to an adjacent fret.
Curl your fingers until your fingertips are on one of the strings. Be sure to keep the tips of your fingers close to the frets as you play.