Retail investors are prone to psychological biases that make day trading difficult. They tend to sell winners too early and hold losers too long, what some call “picking the flowers and watering the weeds.” That’s easy to do when you get a shot of adrenaline for closing out a profitable trade. Investors engage in myopic loss aversion, which renders them too afraid to buy when a stock declines because they fear it might fall further.

The common use of buying on margin (using borrowed funds) amplifies gains and losses, such that substantial losses or gains can occur in a very short period of time. In addition, brokers usually allow bigger margin for day traders. In the United States for example, while the initial margin required to hold a stock position overnight are 50% of the stock's value due to Regulation T, many brokers allow pattern day trader accounts to use levels as low as 25% for intraday purchases. This means a day trader with the legal minimum $25,000 in his account can buy $100,000 (4x leverage) worth of stock during the day, as long as half of those positions are exited before the market close. Because of the high risk of margin use, and of other day trading practices, a day trader will often have to exit a losing position very quickly, in order to prevent a greater, unacceptable loss, or even a disastrous loss, much larger than her original investment, or even larger than her total assets.
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.

Many orders placed by investors and traders begin to execute as soon as the markets open in the morning, which contributes to price volatility. A seasoned player may be able to recognize patterns and pick appropriately to make profits. But for newbies, it may be better just to read the market without making any moves for the first 15 to 20 minutes. The middle hours are usually less volatile, and then movement begins to pick up again toward the closing bell. Though the rush hours offer opportunities, it’s safer for beginners to avoid them at first.
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