Dreams, that hopefully will mature into goals and life plans, are totally tied in with your passions in life. What are you passionate about? What is it that your friends say (or at least think), “You are always talking about that”? Discover your passions.
What type of book do you read the most? What type of movies to you enjoy? We often identify with characters that are like we want to be, or are in situations that we would be drawn to (fictional or true-life). Huge fan of CSI? Perhaps you could be passionate about justice, or discovering the truth, or science.
Are you drawn to the biographies of certain people? If so, find out why. Perhaps you are drawn to people who could share the same passions as you.
I throw out these thoughts as a quick sketch of a method of self-examination. If you think along these lines, you will probably come up with your own method. Think of discovering your passions as a mystery to solve, or a land to explore, or a house to build, or whatever analogy captures your interest. Your methods of self discovery tell a lot about your character in themselves.
And try out the other ideas in this thread. Who knows what will work the best for you?