What?
Technical analysis is done by looking at previous price, and volume data. Technical analyst look at past chart of price and different indicator to make prediction about the future prices. The human emotion is an important aspect here. Their willingness to buy stock at a certain price will determine future price. This analysis assumes that price moves at trend, and history repeats itself. It is believed that this analysis is more art than science. Because of that, there has been plenty of critics to this analysis, due to lack of evidence of it's performance. But it is still a popular method in the world, through its easiness. Critics also came from well known fundamental analyst, Warren Buffet. It is also inconsistant with market hypothesis, like Efficient Market Hypothesis (EMH) and Random Walk Hypothesis.

How?
The most popular method used in this analysis is support and resistance, bollinger band, moving average, momentum, stochastic oscillator and indicator such as MACD. Moving Average is the average closing price. They also look at pattern at chart like the popular head and shoulder. There at a lot of software out there which can help you with this kind of analysis.

How’s the performance?
Sometimes it works sometimes it don’t. But due to it’s activeness in trading, it has high cost transaction. So you must deduct your return with this transaction cost.

For who?
Technical is for short term player. They are usually very active in their trades. Whatever the price movement, they can go in by going long or short. This analysis is easy to do, especially by looking at charts, making is a very popular analysis.