Ask your dentist during your next dental checkup and cleaning for recommendations about what you should be buying based off your individual needs, your particular dental health state, etc.
Some common suggestions among dental professionals are to look for toothbrushes with soft bristles, as hard bristles damage your teeth and gums, choose a toothbrush head size that touches one or two teeth at a time, use a toothpaste containing fluoride approved by the ADA, consider using mouthwash to further fight plaque and gingivitis, and don’t forget floss!
Consider investing in an electric toothbrush, as these have been proven to improve oral health beyond what a manual toothbrush can do by removing plaque, reducing gingivitis and eliminating teeth staining. They’ve also been shown to minimize the amount of plaque on the teeth of people with periodontal disease.
Do your research on what products fit your needs best, and don’t forget to ask your dentist for recommendations.