Make a plan and stick to it. Navigating New Year's Eve in Times Square is akin to planning a military operation. You need to have all of your logistical information in place, know your target and have a plan to complete your mission. Plan well and plan early.
Dress warmly. Remember you'll be standing in freezing or below zero temperatures for a long period of time. Layers are key. Scarves, hats and gloves are a must.
Eat before you get there and take snacks. There aren't vendors in the area and no one is going to save your spot just because you want to go catch a meal in a nearby restaurant.
Use the restroom before you get there. There are no port-a-potties and while you could jump out of line to use a restroom somewhere nearby, don't expect to get that prime spot back.
Get their early--very early. Many people begin to arrive at noon on December 31st. Arriving late means having a lousy view of the ball dropping and if that happens there's no reason for you to go in the first place.
Stay hydrated. It's cold and you're wearing layers to stay warm, so you may be sweating and could become dehydrated. While being hydrated and having no ready access to restrooms seems contradictory, it's a contradiction that has to be worked out.
Enjoy the atmosphere. It's New Year's Eve in Times Square. Chat it up with your friends. Get to know new people. And have someone nearby for that all important New Year's kiss.