What is the best advice you can give to person who have hepatitis b?

HCC risk. You should follow closely with a gastroenterologist as you may be at risk for hcc (cancer of the liver) and might need regular screening.
Help your liver. The best advice would be not to harm your liver more than it is already. Lead a healthy lifestyle - avoid alcohol, known toxins, including meds, unhealthy diets - cola products, high fat foods. If you hepatitis is active, you may consider having it treated and therefore eradicate the virus. If it is dormant, check your liver enzymes periodically to make sure it remains the same.
See a physician. Tje first thing you should do is see a hepatologist or gastroenterologist to assess the status of your hepatitis b. Current treatments are highly effective, but not all people require treatment.