Smaller moves, easier to obtain - A change in price results from imbalance of buying and selling powers. Most of the time within a day, prices stay stable, moving within a small range. This means neither buying nor selling power control the situation. There are only a few times which price moves towards one direction, i.e. either buying or selling power controls the situation. It requires bigger imbalances for bigger price changes. It is what scalpers look for - capturing smaller moves which happen most of the time, as opposed to larger ones.
Scalping highly liquid instruments for off-the-floor day traders involves taking quick profits while minimizing risk (loss exposure). It applies technical analysis concepts such as over/under-bought, support and resistance zones as well as trendline, trading channel to enter the market at key points and take quick profits from small moves. The basic idea of scalping is to exploit the inefficiency of the market when volatility increases and the trading range expands. Scalpers also use the "fade" technique. When stock values suddenly rise, they short sell securities that seem overvalued.
But this description of swing trading is a simplification. In reality, swing trading sits in the middle of the continuum between day trading to trend trading. A day trader will hold a stock anywhere from a few seconds to a few hours but never more than a day; a trend trader examines the long-term fundamental trends of a stock or index and may hold the stock for a few weeks or months. Swing traders hold a particular stock for a period of time, generally a few days to two or three weeks, which is between those extremes, and they will trade the stock on the basis of its intra-week or intra-month oscillations between optimism and pessimism.
In addition to knowledge of basic trading procedures, day traders need to keep up on the latest stock market news and events that affect stocks—the Fed's interest rate plans, the economic outlook, etc. So do your homework. Make a wish list of stocks you'd like to trade and keep yourself informed about the selected companies and general markets. Scan business news and visit reliable financial websites.