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.

Fundamental analysis usually involves using a company's financial statements, discounted cash flow modeling and other tools to assess a company's intrinsic value. Scalpers may trade on news or events that drastically affect a company’s value immediately after its release. In some cases, they may also use short term changes in fundamental ratios to scalp trades but typically they focus mostly on the technical charts.

There is no special qualification required to become a day trader. Instead day traders are classified based on the frequency of their trading. FINRA and NYSE classify day traders based on whether he or she trades four or more times during a five-day span, provided the number of day trades is more than 6% of the customer's total trading activity during that period or the brokerage/investment firm where he or she has opened an account considers him a day trader. Day traders are subject to capital and margin maintenance requirements.
Volatility is the name of the day-trading game. Day traders rely heavily on a stock’s or market’s fluctuations to earn their profits. They like stocks that bounce around a lot throughout the day, whatever the cause: a good or bad earnings report, positive or negative news, or just general market sentiment. They also like highly liquid stocks, ones that allow them to move in and out of a position without much affecting the stock’s price.
The bid–ask spread is two sides of the same coin. The spread can be viewed as trading bonuses or costs according to different parties and different strategies. On one hand, traders who do NOT wish to queue their order, instead paying the market price, pay the spreads (costs). On the other hand, traders who wish to queue and wait for execution receive the spreads (bonuses). Some day trading strategies attempt to capture the spread as additional, or even the only, profits for successful trades.[18]
Rebate trading is an equity trading style that uses ECN rebates as a primary source of profit and revenue. Most ECNs charge commissions to customers who want to have their orders filled immediately at the best prices available, but the ECNs pay commissions to buyers or sellers who "add liquidity" by placing limit orders that create "market-making" in a security. Rebate traders seek to make money from these rebates and will usually maximize their returns by trading low priced, high volume stocks. This enables them to trade more shares and contribute more liquidity with a set amount of capital, while limiting the risk that they will not be able to exit a position in the stock.[16]
Day trading is traditionally defined as buying and selling stock, options, or commodities during the same trading day and be have your positions closed by the end of the trading session. In the past, day trading had been reserved for financial companies and professional investors. A large percentage of day traders work for investment firms or are specialists in fund management. With the advance of technology, day trading has continue to grow among the casual trader working from home.
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.