To compare health insurance plans online, start by identifying your healthcare needs, including coverage for pre-existing conditions, preferred doctors, and hospitals. Use reputable comparison websites to view multiple plans side-by-side, focusing on premiums, deductibles, out-of-pocket maximums, and coverage benefits. Check the network of providers to ensure your healthcare professionals and facilities are covered. Review the summary of benefits for details on services covered, including preventive care, prescriptions, emergency services, and mental health treatment. Finally, consider customer reviews and financial strength ratings of insurance companies to gauge their reliability and service quality. This comprehensive approach helps in making an informed decision tailored to your specific health care needs.