The number of entries a trader should open in one trading session depends on their trading strategy, risk tolerance, and market conditions. Some traders prefer to focus on a single trade at a time, while others may have multiple trades open simultaneously. It's important to avoid overtrading, as this can lead to poor decision-making and increased risk. Traders should also consider the impact of correlations between trades and avoid opening positions that could potentially amplify losses. Ultimately, the number of entries a trader opens should be based on careful analysis, risk management, and adherence to their overall trading plan.