Encourage healthy lifestyles, exercise, fresh air, sunlight. Encourage and make available for prophylactic use immune system boosters. Encourage those in high-risk demographics to reduce contacts if possible. Provide vaccines to all those who want them.
Theses just isn't viable. People were encouraged to wear masks at the beginning but no one did it. You think you'll be able to encourage people to get out and do exercise and suddenly live a "healthy lifestyle"? The government has been encouraging that for my entire life, why would people start listening now?