General Russian Orthodox church etiquette rules for women, excluding the rules of particpating in a sermon:
1. Headcovering - the best is a headscarf
2. Garments - observe the Roman Catholic rule of covered elbows and knees plus wearing a skirt or a dress - no pants or shorts. No decolette.
3. No visible makeup, no lipstick at all - the Orthodox have a tradition of kissing icons or relics. Lipstick stains are hardly cleaned apart of the fact that it's considered not pious. Earrings is ok, piercing elsewhere isn't.