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.
A scalp trader can look to make money in a variety of ways. One method is to have a set profit target amount per trade. This profit target should be relative to the price of the security and can range between .%1 - .25%. Another method is to track stocks breaking out to new intra-day highs or lows and utilizing Level II to capture as much profit as possible. This method requires an enormous amount of concentration and flawless order execution. Lastly, some scalp traders will follow the news and trade upcoming or current events that can cause increased volatility in a stock.
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.” 
ECN/Level 2 quotes: ECNs, or electronic communication networks, are computer-based systems that display the best available bid and ask quotes from multiple market participants and then automatically match and execute orders. Level 2 is a subscription-based service that provides real-time access to the Nasdaq order book composed of price quotes from market makers registering every Nasdaq-listed and OTC Bulletin Board security. Together, they can give you a sense of orders being executed in real time.
Day traders are attuned to events that cause short-term market moves. Trading the news is a popular technique. Scheduled announcements such as economic statistics, corporate earnings or interest rates are subject to market expectations and market psychology. Markets react when those expectations are not met or are exceeded, usually with sudden, significant moves, which can benefit day traders.
Identify a stock or ETF where the weekly trend is up and the bottoms on the daily bar chart tend to be short and sharp. Analyze how the stock or ETF has behaved since the beginning of the trend. If it has returned to the moving average 3 times and penetrated it by an average of 1.5% of its price, place a buy order approximately 1% of the instrument's price below the moving average, a little more shallow than the previous declines.
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.
Retail day traders are competing with professionals. Pros know the tricks and traps. They have expensive trading technology, data subscriptions and personal connections. They’re perfectly outfitted to succeed, and even then they often fail. Among these pros are high-frequency traders, who are looking to skim pennies or fractions of pennies — the day trader’s profit — off every trade. It’s a crowded field, and the pros love to have inexperienced investors join the fray. That helps them profit.