Warren Buffett's greatest investment advice: “If you invest in stocks, you must be mentally prepared to watch them drop 50% or even 80% and stay calm.” 1. Buy when others panic. 2. Focus on 5–10 companies you truly believe in, don’t diversify into 50. 3. Don’t obsess over daily price movements. 4. Study the logic and fundamentals, don’t trade based on candlestick charts. 5. Add positions during big dips, don’t chase during big rallies. 6. Never sell based on emotions. 7. Watch financial reports, not the noise from financial media. 8. Hold good stocks for years or even decades, not just weeks. 9. Pay attention to catalysts, don’t blindly trust candlestick charts. 10. Treat volatility as an opportunity. 11. Don’t check your account every hour. 12. Invest with a 10–20 year perspective. The market rewards patience and punishes impulsiveness.