Day trading is a popular tactic that can be both rewarding and challenging. It involves buying and selling financial instruments within the same trading day. For success in day trading, an individual needs disciplined strategies and a comprehensive understanding of the market.

Day traders do not hold positions overnight. This speculative trading strategy can yield substantial profits but also comes with a high level of risk. Hence, a strategic and well-calculated approach is crucial.

The ability to possess a range of skills from quick decision-making abilities to intense discipline. Furthermore, a deep market understanding, technical analysis skills, and sound judgement are essential for success as day trader.

Risks and challenges are synonymous with day trading. Volatilities and unpredicted market shifts can often lead to substantial losses. Moreover, day trading requires a significant investment of time and resources. Hence, before delving into day trading, it's pivotal to assess your financial goals, trade the day risk tolerance, and investment resources.

Various financial instruments are available for day trading. From stocks and forex to futures and options, traders can choose what suits their trading style best. Each instrument comes with its own set of benefits and drawbacks, so understanding your investment goals and risk tolerance is critical to choose the right instrument for trading.

A solid trading plan holds of utmost importance in achieving success in day trading. The plan should include details like the financial instruments one intends to trade, the risk tolerance level, and the profit targets. Incorporating risk management strategies such as stop-loss orders into the plan is also beneficial.

Continuously monitoring the markets plays an inevitable role in successful day trading. Keeping a close watch on international news, economic events, macroeconomic indicators, and market trends is essential for day traders. Such monitoring equips traders with insights into potential trading opportunities and risk factors.

Despite the initial challenges, with discipline, effective risk management, and patience, day trading could turn into a profitable investment strategy. However, remember that day trading, like any investment strategy, does not assure profits and is subject to market risks. Therefore, it requires careful analysis and vigilant consideration before investing.