No, it's not necessarily useless to make resolutions at the start of a new year. After all, God's will is for us to become better persons and with His help we can.
My own resolution for this coming year is very simple: to grow closer to Christ so I may become more like Him. This is God's will for us, and no matter how young or old we are, His plan never changes. This was the apostle Paul's goal: "Not that I have already obtained all this, or have already been made perfect ... But one thing I do ... I press on toward the goal" (Philippians 3:12,14).
What does it mean to become more like Christ? First, it means to become more like Him in our character in our love for others, our patience, our joy and our rejection of sin. It means also becoming more like Him in His concern for our world a world that desperately needs the hope only He can give. It means as well becoming more like Him in His commitment to do God's will.
Yes, many people make long lists of resolutions and promptly break them or forget them. But this won't happen if you first ask God to show you what kind of person He wants you to be. Let the psalmist's prayer become yours: "Search me, O God, and know my heart ... and lead me in the way everlasting" (Psalm 139:23-24). Then ask Him every day for the strength to become that person.