Blessed are they that mourn, for they shall be comforted.

How?
By others? "willing to mourn with those that mourn and comfort those that stand in need of comfort"
By turning to the Lord? "For thus saith the Lord; Sing with gladness for Jacob, and shout among the chief of the nations: publish ye, praise ye, and say, O Lord, save thy people, the remnant of Israel.

Behold, I will bring them from the north country, and gather them from thecoasts of the earth, and with them the blind and the lame, the woman with child and her that travaileth with child together: a great company shall return thither.

They shall come with weeping, and with supplications will I lead them: I will cause them to walk by the rivers of waters in a straight way, wherein they shall not stumble: for I am a father to Israel, andEphraim is my firstborn.

Hear the word of the Lord, O ye nations, and declare it in the isles afar off, and say, He that scattered Israel will gather him, and keep him, as a shepherd doth his flock.

For the Lord hath redeemed Jacob, and ransomed him from the hand of him that was stronger than he.

Therefore they shall come and sing in the height of Zion, and shall flow together to the goodness of the Lord, for wheat, and for wine, and for oil, and for the young of the flock and of the herd: and their soul shall be as a watered garden; and they shall not sorrow any more at all.

Then shall the virgin rejoice in the dance, both young men and old together: for I will turn their mourning into joy, and will comfort them, and make them rejoice from their sorrow.

And I will satiate the soul of the priests with fatness, and my people shall be satisfied with my goodness, saith the Lord.
By the Holy Ghost? "the comforter"

It seems to be more likely if you are living a repentant life (Mormon 2: 12-14).

Lessons for me? Be willing to mourn and comfort others. Learn what is helpful and what is not helpful. Keep repenting; trying to make the precepts God teaches a natural part of you, turning to Him. Be responsive to the influence of the Holy Ghost as a source of comfort. Recognize it. Take it to heart.

Much to be learned.