What are best immunity boosting tips that one can adapt during this corona virus time?

Several things: I agree with Dr. Fowler so see her answer. I'd add meditation and other stress-reduction techniques. While there are no "magic pills" there is evidence that certain supplements can boost your immunity. I would take Vit C 1000 mg 2-3x/day, Vitamin D 5000 iu/day, Zinc 30 mg/day with food and the herb Andrographis 400 mg or 2 dropperfuls of tincture daily. Also minimize sugar, which impairs immunity.