What are some natural ways to improve blood circulation?

Enhance nitric oxide. L-arginine (if < 40yo and no heart disease), neo40, resveratrol, aerobic exercise, foods that generate nitrix oxide, e.g. Kale, spinach, arugula. Acupuncture, green tea, hot baths. If you have varicose veins or spider veins, also look into butcher's broom supplement.