How about, "I'll do it tomorrow".
This is the biggest load of garbage that can ever be stated. If you really want to do it, then why wait until tomorrow? But the funny thing is, we hear this so much that we even become numb to it. When a person says, " I need to go on a diet. You know what, I'm gonna start on Monday." But today is Thursday, so why are you waiting four days to start? No one really believes that they will follow through with this sudden declaration. And why? Because if they were serious they would start immediately. If you see you need to do it, why not start today, or tomorrow at the latest.
The truth is we say these things to comfort ourself. We want to convince ourselves that if we just have a few more days to prepare, then we will finally be ready to make a change. But that is not how it works. Change comes when we decide on something and act. Once I know I need to do something, then the next step should be to start on it right away. I myself have been a victim of this excuse, "it's no point in starting in the middle of the week. I might as well start afresh next week." But normally, when Monday comes, then you say Tuesday, then on Tuesday you say Wednesday. Then on Wednesday, you say there's no need to start in the middle of the week, I will start on Monday. And the vicious cycle continues.
The point is a procrastinator will go nowhere, because he is always finding a reason why not to go. Action is the only remedy. When you think it, if it's right and you know you need it, then do it. Don't let time slow you down. Momentum is so important. Many times a person has a great idea, but lacks the go ahead to get it done. If you truly believe in it, then go ahead and jump in. The attitude of a winner is simple," I'd rather live with failure than to die knowing I never tried." But the funny thing is, if you give your best everyday, and don't procrastinate when action is needed, I have a hard time believing you will fail.