You've built your bad habits for years - so do not expect them to be solve overnight. Create a reasonable schedule based on the goals that you believe you can accomplish in one week, for example. Setting overambitious goals and then failure in them in a moment of disappointment may convince you to take this as the evidence that it is "impossible" to achieve any change! And this can eventually fall into the self-pity victim mode. If you chronically late for 20 - 30 minutes to each of your meetings, set a goal of setting out early say one hour earlier so that if you ever late by 30 minutes again, at least you are still early by 30 minutes. (It will definitely create a surprise reaction instead of annoying other people.) Instead of late by half an hour, this time you will definitely be early by half an hour, and definitely it is a good change for the start!

Please refer to the book for more details on this activity.