He had a very significant attribute, a relationship with God
He was content with his place, a shepherd who can play a harp and worshiper of God and developed the skills of a shepherd, knowing the terrain, including the ability to protect his sheep wIth a sling.
It was this seemingly limited inglorious ability that propelled him to leadership and notability
It was his ability and history of killing the bear and the lion that prepared him for the greater challenge - defeating Israel's greatest enemy the army of Philistines by defeating their champion Goliath.
The point is embrace the gift and the calling God has givien be faithful where you are and God will bless you where you are and promote you accordingly.