You have to start from some were first before stoping, because it's not going to be easy to stop it why because it has become part of you and to stop it will not be that easy.
You just need God's grace to stop doing bad because doing bad is the most easiest thing to do More than doing good, doing good is kind of difficult that's when the grace of God comes in to help you.
Because it's not of you that willet but God our father who show us mercy daily, if you are thinking you can just stop doing bad on your own then you are getting it wrong, you need help from above.
So desire to do God's will today and not bad anymore.