"The Clean Slate"
To really understand oneself and the world better, one should start with a clean slate.
Erase all the criss-crosses of the chalk on it, all the dust that has settled on it, and wipe it clean with water and cloth.
Then restart writing on it, this time do it very carefully and slowly.....
Start with "Should I live or should I die? Why should I want to live?" Give this question some deep thought.
Then go to "What should I do with my time here? What do I want?". Throw in the "Who am I?" and "What have I been doing all this time?" in there somewhere.
After posing various questions, and writing the answers down, which can take days, weeks, months or years, you should have a new perspective on which to make judgements, decisions, etc.
Once the slate is clean, and has statements which only have been put there with deliberate thought, we become open to new ways of thought -- this is its biggest advantage. So at that point, you view whatever you had learned, or got misguided in the past, in a completely different light.
However, I have noticed that this sometimes, at least in my case (see this post and this post) and someone else's I know, results in an individualistic outlook. If one really starts thinking -- "what do I really want", he goes in the "alone, egotist, its-my-life" individualistic approach.
At that point, Yoga, meditation and in general spirituality start helping. Getting to know the world consciousness start having more meaning. "God", "religion", "spirituality", "yoga", "meditation" all start looking as synonyms of non-egoism and dissolved-boundaries-between-self-and-everything-else.
Science, spirituality, psychology, philosophy, technology, culture, relationships, etc start looking as the mirrors of the a kaleidoscope using the light of "ego" and "the non-living".
And then you go crazy, and visit a shrink. Just kidding! :)
UPDATE: Rishi pointed to his very splendidly written insights in this blog post, which I commented to as well.