"You can't break a bad habit by throwing it out the window. You've got to walk it slowly down the stairs"
I think essentially what Mark Twain is trying to say is this; a habit is formed over many weeks, months and years, and it can only be broken slowly over time. Time spent trying and failing, and trying again. Whatever habit you are trying to break in your life, keep trying, and don't allow yourself to give up.
~Written by Shannon of Faith~Hope~&~Love~