>>1
It doesn't. Period. Anyone who says otherwise is either: a) selling something, or b) lucky. You'll see some investors who claim to use TA to make money, and a few might even be telling the truth. It doesn't mean their flavor of TA works, it means that if you throw a million idiots all picking stocks at the market at once, at least five or six will make money on the basis of chance alone.
The best strategy for coming out ahead in the stock market is to build a diversified -- really diversified, not just "oh look I hold four different index funds" diversified -- portfolio of assets that cover a broad range of risks, pay close attention to and minimize your fees and tax implications (don't be afraid to sell at a loss to offset gains, and don't do dollar cost averaging because the broker fees will fucking murder you), and don't fucking touch it for the next twenty years except to re-balance back to your target asset allocations.
In the long run you can earn an average of 8-9% per year without a huge amount of risk.