what type of Criteria shod i use to select member of the month & year

It’s hard to single someone out for a subjective award, you may want to make up a running list of things to look for, even “for extra effort” or “for taking a Yoga class” or “losing 2 inches off his or her waist in X amount of time”
Use specific goal setting criteria and keep in mind that everyone likes to be acknowledged in some manner!