Before heading out with your pup, it's a good idea to take him to a local training class. No one likes a yipping dog that nips at interested hands, even if he's supercute. Proper training teaches your dog how to sit, stay, and follow directions when out in public.
Along with working with your dog on his etiquette, if you've got a small dog, carrier-train your pooch by enticing him into your bag with treats and positive reinforcement. Begin by inviting your pup into the carrier bag while it's on the ground. Try encouraging him to spend a bit of time in the carrier every day. Once he's comfortable, try lifting the bag while talking calmly. Continue working slowly with your dog until he's comfortable being carried in the carrier bag, and then you're ready to hit the town.