Making a list is one of the best ways to organize your thoughts. Even in the face of a heady question like “who am I?” or “what do I really want out of life?”, a list can be remarkably useful. Once you have a list, keep it close at hand and add to it, remove from it, or alter it as you see fit. Over time, a clearer picture of your priorities will begin to emerge.  Start by refining your basic question. It's difficult to think about yourself objectively, so the broader your question is, the more trouble you'll have coming up with comprehensive answers to it. Instead of just asking “what is my true identity?”, ask “what personality traits do I admire and try to exemplify?”, or “what do I value in a friend?”. You can ask yourself as many of these questions as you want, but keep a separate list for each. Don't resort to pat answers. If you're listing things you look for in your friends, words like “loyalty” and “reliability” are sure to pop into your mind first. That's fine, but try to think beyond the word to its meaning – do you really rely on loyalty in your friends, by telling them secrets and expecting them to be there for you at every turn, or is something else even more important to you? Maybe you'll realize that you look for friends who are more socially awkward than you, so that you can feel like the life of the party when you spend time together. Such realizations are what will help you begin to know yourself better. List negatives, but don't dwell on them. To truly understand yourself, it's important to know your weaknesses, fears, disappointments, and dislikes as well as the more positive aspects of your life. However, that doesn't mean you should focus on such things exclusively. If you find that there's a lot about yourself you don't like, try to come up with ideas about why you might exhibit those characteristics, and how you can change them. If your lists all seem to begin with “I hate my job,” try to come up with other, more positive lists: dream jobs, or things you wish you could change about your current job. As your lists grow and change over time, it's helpful to come back to them regularly and read them over side by side to divine the items that are most important to you. However, self-focused exercises will only carry you so far. To truly expand your self-understanding, you must delve into philosophical, spiritual, and artistic works.  You don't have to read everything. Not everybody finds the idea of reading Plato or Sartre appealing. Though you'll get the most out of such authors by taking the plunge and reading their important works cover to cover, you can also get a solid and helpful overview simply by reading abridged explanations of their philosophies. There's no shame in reading a Wikipedia article and some Cliff's Notes in lieu of the collected works of Arthur Schopenhauer, as long as what you read helps expand your self-understanding. Try fiction instead. Often, great works of literature also reflect philosophical systems of thinking, and reading such works can be a much less threatening prospect than tackling the dry foundational books. The famous Russian author Fyodor Dostoyevsky, for example, wrote stories informed by existentialist philosophy. Don't neglect the spiritual. Even if you've never felt particularly spiritual, reading the poems of Walt Whitman or the writings of ancient Chinese spiritual philosopher Laozi (Lao Tzu) can help you understand yourself in ways that logical analysis never will. If you've always had very rigid religious beliefs, don't be afraid to read the mythologies and philosophical works of other religions, either – very often, you'll find interesting and useful insights that pose no threat to your own belief system. As a human being, you're extraordinarily complex, in ways you might never even realize. Understanding yourself completely is essentially impossible, as you're always changing, considering, and processing and analyzing new information and insights. However, you can achieve a practical, useful level of self-understanding. Be patient with yourself, and stay open to new thoughts and realizations. The better you know yourself, the more effectively you can control yourself and the general direction of your life. A part of accepting your own overwhelming complexity is acknowledging the complexity of others, as well. Sometimes, things are simply out of your control – that is the way of the world, both in nature and society. Just because things don't work out the way you tried to make them work out doesn't mean you're doing anything wrong. Human beings are social animals, and there's no substitute for face-to-face interaction to really help you understand yourself. You can tell yourself you're a certain way, or that you'll react in a certain way in a given situation, but you often don't know for sure how you'll really feel about it until it happens. Place a high value on anyone with whom you can have a heartfelt talk and/or a spirited discussion. You may find such people in any of a number of places – a true friend, a supportive family member, or just an acquaintance who loves to talk about the same things that interest you. You can even hire a counselor or psychiatrist if you need a relatively impartial sounding board for your thoughts.

Summary:
Make lists and keep them. Read yourself and others. Accept your complexity. Look to outside sources.