What is a good oral hygienic routine to prevent swollen gums?

Brushing, flossing. The best oral hygiene routine starts with a healthy mouth. To keep plaque and tarter from building up under and at the gum line, brush for 3 minutes on all tooth surfaces-cheek side, tongue side and on the chewing surface. Flossing each tooth is also necessary, sliding the floss along the tooth surface and under the gum. Brush your tongue also. Keep your mouth plaque/bacteria free for health.
Brush, floss, seeDDS. Floss daily (or use water pic type device), brush after meals; avoid concentrated sweets (including dried fruit); see your dentist regularly for cleanings (at least twice a year). Diet ample in vitamin c can help keep gums healthy (doesn't generally need supplements for this).