Technical analysis uses past stock and security price data and trading volume to identify patterns and trends in prices. These trends are then used to predict future price movements and identify good entry and exit points. Key aspects of technical analysis include identifying uptrend and downtrend lines using charts, understanding support and resistance levels, analyzing trading volume changes, and using indicators and oscillators to validate trends identified by price and volume data. The overall goal is to predict short-term price movements rather than long-term investments.