The first EMA (50) must be positioned above the second EMA (100). When this has occurred, it is essential to wait until the price comes back to the EMAs. In turn, the Stochastic Oscillator is exploited to cross over the 20 level from below. The moment you observe the three items arranged in the proper way, opening a long (buy) order may be an option.
The second type of scalping is done by purchasing a large number of shares that are sold for a gain on a very small price movement. A trader of this style will enter into positions for several thousand shares and wait for a small move, which is usually measured in cents. Such an approach requires highly liquid stock to allow for entering and exiting 3,000 to 10,000 shares easily.
These developments heralded the appearance of "market makers": the NASDAQ equivalent of a NYSE specialist. A market maker has an inventory of stocks to buy and sell, and simultaneously offers to buy and sell the same stock. Obviously, it will offer to sell stock at a higher price than the price at which it offers to buy. This difference is known as the "spread". The market maker is indifferent as to whether the stock goes up or down, it simply tries to constantly buy for less than it sells. A persistent trend in one direction will result in a loss for the market maker, but the strategy is overall positive (otherwise they would exit the business). Today there are about 500 firms who participate as market makers on ECNs, each generally making a market in four to forty different stocks. Without any legal obligations, market makers were free to offer smaller spreads on electronic communication networks than on the NASDAQ. A small investor might have to pay a $0.25 spread (e.g. he might have to pay $10.50 to buy a share of stock but could only get $10.25 for selling it), while an institution would only pay a $0.05 spread (buying at $10.40 and selling at $10.35).
In parallel to stock trading, starting at the end of the 1990s, several new market maker firms provided foreign exchange and derivative day trading through electronic trading platforms. These allowed day traders to have instant access to decentralised markets such as forex and global markets through derivatives such as contracts for difference. Most of these firms were based in the UK and later in less restrictive jurisdictions, this was in part due to the regulations in the US prohibiting this type of over-the-counter trading. These firms typically provide trading on margin allowing day traders to take large position with relatively small capital, but with the associated increase in risk. The retail foreign exchange trading became popular to day trade due to its liquidity and the 24-hour nature of the market.
There is a commonly quoted statistic that only about 5 percent of day traders succeed. This is a good approximation. Most people who try day trading will not succeed, yet most of them do not practice everyday for six months to a year either. Time investment and quality practice increase a day traders chances of being in the 5 percent that are successful.
Sincere interviewed professional day trader John Kurisko, Sincere states, Kurisko believes that some of the reversals can be blamed on traders using high-speed computers with black-box algorithms scalping for pennies. “That’s one of the reasons many traders get frustrated with the market. The timing is not like it used to be, and many of the old rules don’t work like before.” 
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.
Day trading is the act of buying and selling a financial instrument within the same day or even multiple times over the course of a day. Taking advantage of small price moves can be a lucrative game—if it is played correctly. But it can be a dangerous game for newbies or anyone who doesn't adhere to a well-thought-out strategy. What's more, not all brokers are suited for the high volume of trades made by day traders. Some brokers, however, are designed with the day trader in mind. You can check out our list of the best brokers for day trading to see which brokers best accommodate those who would like to day trade.