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.
The profit potential of day trading is perhaps one of the most debated and misunderstood topics on Wall Street. Internet day trading scams have lured amateurs by promising enormous returns in a short period. The idea that this kind of trading is a get-rich-quick scheme persists. Some people day trade without sufficient knowledge. But there are day traders who make a successful living despite—or perhaps because of—the risks.
A scalper intends to take as many small profits as possible, without letting them evaporate. This is the opposite of the "let your profits run" mindset, which attempts to optimize positive trading results by increasing the size of winning trades while letting others reverse. Scalping achieves results by increasing the number of winners and sacrificing the size of the wins. It's not uncommon for a trader with a longer time frame to achieve positive results by winning only half or even less of his or her trades – it's just that the wins are much bigger than the losses. A successful scalper, however, will have a much higher ratio of winning trades versus losing ones, while keeping profits roughly equal or slightly bigger than losses.
By aggressively trading on margin he can produce 5% daily profits on the 100k buying power he will grow their 25k cash at the rate of 20% per day. The risk of course is that he will make a mistake that will cost him everything. Unfortunately, this is the fate of 9 out of 10 traders. The cause of these career ending mistakes is a failure to manage risk.
Swing trading is actually one of the best trading styles for the beginning trader to get his or her feet wet, but it still offers significant profit potential for intermediate and advanced traders. Swing traders receive sufficient feedback on their trades after a couple of days to keep them motivated, but their long and short positions of several days are of the duration that does not lead to distraction. By contrast, trend trading offers greater profit potential if a trader is able to catch a major market trend of weeks or months, but few are the traders with sufficient discipline to hold a position that long without getting distracted. On the other hand, trading dozens of stocks per day (day trading) may just prove too white-knuckle of a ride for some, making swing trading the perfect medium between the extremes.
Originally, the most important U.S. stocks were traded on the New York Stock Exchange. A trader would contact a stockbroker, who would relay the order to a specialist on the floor of the NYSE. These specialists would each make markets in only a handful of stocks. The specialist would match the purchaser with another broker's seller; write up physical tickets that, once processed, would effectively transfer the stock; and relay the information back to both brokers. Before 1975, brokerage commissions were fixed at 1% of the amount of the trade, i.e. to purchase $10,000 worth of stock cost the buyer $100 in commissions and same 1% to sell. Meaning that to profit trades had to make over 2 % to make any real gain.
News provides the majority of opportunities from which day traders capitalize, so it is imperative to be the first to know when something significant happens. The typical trading room contains access to the Dow Jones Newswire, constant coverage of CNBC and other news organizations, and software that constantly analyzes news sources for important stories.  
Mutual funds are off-limits for intraday trading. The design of these funds is for the long-term investor, and they can only be bought and sold through a broker or the fund's investment company. Also, a mutual fund's price posts only once, at the close of the trading day. This price is known as the net asset value (NAV) and reflects all of the intraday movement of the fund's assets, less its liabilities, calculated on a per-share basis.

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.