I've found that most people who make long lists of New Year's resolutions usually end up breaking them before too many weeks are up. Perhaps your friends just didn't make very many resolutions!
But as you've discovered, it's far easier to make a resolution than to keep it. Why is that? It is because good intentions aren't enough. Instead, we need the inner strength to see them through and that's what we usually lack. By ourselves, we are weak and have a very hard time changing our old ways of living even when we know what's best for us.
That's why we need Christ in our lives, because when we open our hearts and lives to Him, He gives us a new desire to do what is right. But more than that, He gives us a new strength to do what is right the strength of the Holy Spirit. This is why the Apostle Paul could say, "I can do everything through him (Christ) who gives me strength" (Philippians 4:13).
Let me urge you to do two things. First, if you have never done so, ask Jesus Christ to come into your life. By a simple prayer of faith you can commit your life to Him today. Then turn to Him every day and ask Him to help you turn from sin and live the way you should. Let your prayer be that of the psalmist: "Grant your strength to your servant" (Psalm 86:16).