How can i, naturally, strengthen my gums?

Very simple: Maintain good oral hygiene through brushing and flossing, good healthy diet, and visiting your dentist twice a year for checkup and cleaning ....

Keep em clean,FLOSS!: Your gums don't strengthen, but you can keep them healthy and firm through daily flossing. (skipping a day is like not flossing at all) and vibratory toothbrushing at the gum-tooth interface. (brushing long and hard, up-down, in circles, or sweeping is extremely damaging and you end up skipping over the areas you need to clean.) flossing = 93% oral hygiene, toothbrushing= 6%, rinsing =1%!