Avoiding triggers is the best way to maintain your sobriety. Make a list of people, places, and things that cause you to want to drink. Avoid these triggers as much as possible, especially while attending holiday parties and gatherings where alcohol is being served. If you have relatives that make you want to drink, limit your time around them.
Remember that you also don't have to attend every event you're invited to. Be mindful of where (and with whom) you choose to spend New Year's Eve. New Year's Eve is a drinking holiday, and most gatherings will have Champagne. Do what's best for your recovery, even if that means declining an invite.