You're right; it's probably not worth bothering with resolutions if you start out assuming you're going to fail -- because that's exactly what you'll end up doing. But it doesn't have to be this way, and I suggest you reconsider.
The start of a new year is a good time to stop and look at our lives -- and that's the first step in making any realistic resolutions. What needs to be improved in our lives? What needs to be eliminated -- or added? Most of all, what does God see when He looks at me, and what does He want me to do -- with His help? What is His will for the coming year -- and for my life? The Bible says, "Forget the former things; do not dwell on the past. See, I am doing a new thing" (Isaiah 43:18-19).
Then make sure your resolutions are realistic. Many New Year's resolutions aren't "resolutions" at all; they're only vague dreams or wishes. Don't focus on self-centered goals; focus instead on what God wants to do in your life. Above all, make sure of your commitment to Christ -- and if He means little to you, why not begin the new year by giving your life to Him?
Finally, think through how you can achieve the goals you've set. Pray for God's help; plan what steps you need to take; get others to encourage and help you. May 2012 become the best year you've ever had, as you build your life on the foundation of Christ and His Word.