Sometimes it's hard to recognize when the Holy Ghost is telling you something but Galatians 5:22-23 tells us that some of the "fruits of the spirit" are:
Love
Joy
Peace
Long Suffering
Gentleness
Goodness
Faith
Meekness
Temperance
The way we can know something is true is by the things it produces. Or its fruits. For example, Noah's "fruit" was the ark, Moses parted the Red Sea freeing his people, and Joseph Smith translated the Book of Mormon.
So we have all these "fruits," but how do we know if they are true? It's just like real fruit. You have to try it, taste it yourself to know if it is something you like. People can tell you that strawberries are good but you won't know until you actually try it yourself. So test it out! If you want to know if something is true or you don't know what choice you should make- try it- taste it and pay attention to the "fruits of the spirit." Just as there are different fruits you can eat, there are different fruits, or different ways the spirit works in our lives.
If you feel love, peace, goodness, or faith while and afterwards then it is a good fruit.
My challenge to you is to go try it, test it out. Read the Book of Mormon. If you already have, read it again and pay attention to the feelings and thoughts you get while you are reading and praying about it. I have done this and I know it is real, and that it works. I know Heavenly Father wants us to succeed and be happy in this life. That is why he has given us the Holy Ghost to testify of truths.