Web applications face evolving threats. OWASP Top 10 vulnerabilities remain the most common attack vectors, but new threats emerge regularly. Essential practices include input validation, output encoding, secure authentication, and regular security testing. Implement rate limiting to prevent brute force attacks and use HTTPS everywhere. Consider a Web Application Firewall (WAF) to provide additional protection. Regular penetration testing helps identify vulnerabilities before attackers do. Security is not a destination but a continuous journey. Stay informed about new vulnerabilities and patches. Keep dependencies updated and monitor for suspicious activity.