Receive the Priesthood
44 For you shall live by every word that proceedeth forth from the mouth of God.45 For the word of the Lord is truth, and whatsoever is truth is light, and whatsoever is light is Spirit, even the Spirit of Jesus Christ.46 And the Spirit giveth light to every man that cometh into the world; and the Spirit enlighteneth every man through the world, that hearkeneth to the voice of the Spirit.47 And every one that hearkeneth to the voice of the Spirit cometh unto God, even the Father.
As I think about the most impactful moments of service in the priesthood, this about sums it up. Live by God's word and listen to the Holy Ghost.
But as said earlier, we can't just expect the Holy Ghost to show up. We have to invite him. We have to learn the word of God, live the word of God, and invite the Holy Ghost every day.
That is why the promise at the end of the sacrament prayers is "that they may have His Spirit to be with them" (D&C 20:77). That is why both Joseph Smith and Brigham Young appeared to their successors and told them to "tell the people to be humble and faithful and sure to keep the Spirit of the Lord" (Saints, Vol. 2, Chapter 3, and Saints, Vol. 2, Chapter 44).
Priesthood service requires the Holy Ghost. It takes work for us to receive the Holy Ghost. It takes work for us to receive the priesthood so that we can serve others in God's work and way. And as we receive the priesthood, we become Abraham's seed through the priesthood.