There are several things that greatly enhance our ability to understand the promptings of the Holy Ghost and thereby hear the voice of God.
First is fasting and prayer. When the sons of Mosiah were united with Alma the Younger, they rejoiced in their reunion and acknowledged that because “they had given themselves to much prayer, and fasting,” they had been gifted with the spirit of prophecy and revelation, and “when they taught, they taught with power and authority of God” (Alma 17:3).
Second is immersing yourself in the scriptures. The word of God “will tell you all things what ye should do” (2 Nephi 32:3). The scriptures are a conduit for personal revelation. Your generation is much more versed in holy writ than was mine at your age. You have been taught to read and study the scriptures. I urge you to intensify your study of them. I promise that your ability to hear the voice of the Lord as communicated through the Holy Ghost will increase and improve.
Third is preparing to spend time in the house of the Lord. When the time appropriately comes for you to go to the temple, you will leave the temple “armed with … power” (D&C 109:22) and with the promise that as we “grow up” in our knowledge of the Lord, we will “receive a fulness of the Holy Ghost” (D&C 109:15). The temple is a place of personal revelation. Prepare yourself to enter, for inside the doors of the temple rests the power that will fortify you against the vicissitudes of life.
Fourth is listening to the counsel of your father and mother. They are wise and experienced. Share with them, as my children have shared with me, your fears and concerns. Seek blessings from your father. You should also receive your patriarchal blessing.
Fifth is obedience and repentance. There are certain things you simply cannot do if you want to have the Holy Ghost with you. It is not possible to listen to vulgar lyrics, watch movies filled with sexual innuendo, tamper with pornography on the Internet (or anywhere else for that matter), take the name of the Lord in vain, wear revealing clothing, compromise in any way the law of chastity, or disregard the values of true manhood and womanhood and expect the Holy Ghost to remain with you. Whenever anyone participates in those kinds of activities, it should not be a surprise if feelings of loneliness, discouragement, and unworthiness follow. Do not make the choice to go it alone rather than have the Spirit of the Lord to guide, to protect, to prompt, to warn, and to fill you with peace. Repent if you need to so you can enjoy the companionship of the Spirit.
Women and men who can hear the voice of the Lord, and who respond to those promptings, become invaluable instruments in His hands.