Can God help me discover my true purpose in life or is it something I must figure out on my own?
It is fairly simple, even banal to some:
12 I know that there is nothing better for them, than to rejoice, and to do good so long as they live. 13 And also that every man should eat and drink, and enjoy good in all his labor, is the gift of God. 14 I know that, whatsoever God doeth, it shall be for ever: nothing can be put to it, nor anything taken from it; and God hath done it, that men should fear before him.
Micah 6:
8 He hath showed thee, O man, what is good; and what doth Jehovah require of thee, but to do justly, and to love kindness, and to walk humbly with thy God?
Basically, we should live walking in justice, loving kindness and humility. Helping others when in need, rejoicing in living with family and friends, and rejoicing in our work. (though many have work that isn't fun at all, and many have no work) We should stay away from the forbidden things.
If you do this and have a personal relationship in prayer with God, you are living the kind of life we are supposed to. That is, cherishing and taking care of the treasures of the earth we have been given, keeping it in good health and clean from pollution. Christians are also told, that because we have faith, we speak the gospel of salvation in Christ.