Best dental care routine?

Consistency. Brush at least twice a day. Floss before you brush. Rinse with a Fluoride rinse if you get many cavities. Chew xylitol gum.
Many. Best to see a dentist at least 2X per year, and practice daily home care with proper brushing, flossing, rinses, and avoiding sweet acid foods and beverages like soda.
Good oral hygiene. Brush and floss at least twice a day. Avoid sugar and acidic beverages. Visit your dentist regularly to maintain and address any dental needs.
Great oral hygiene. Floss daily brush twice daily, limit sugar intake especially soda, visit your dentist every 6 months. Cut out tobacco altogether.
Several things... Brushing with a soft tooth brush or sonicare toothbrush at least three times daily. Using an ada accepted toothpaste. Daily flossing with mono-filament floss. Daily tongue scraping. Rinsing with water following between meal foods or drinks if you cannot brush. Xylitol containing gum or mints three times daily to decrease bacteria in the mouth which cause decay.
Floss! Good brushing and flossing, and perhaps use of a good mouthrinse like listerine. If it is just gingivitis then this will be beneficial, but if it's progressed to a more serious form, affecting the bone, your home care will not cure the problem.