In an article in the Sunday New York Times psychology professor David deSteno points out that there actually are two yous involved: the one in the present who intends to do something in the future--exercise more, eat less, make time to write, etc.--and the future you who may decide in the moment that sleeping another hour is just as good for your health as going to the gym, that one little dessert isn't gong to make any difference, and that it makes sense to watch TV instead of writing because the show might inspire you.
When we make promises to ourselves we are in a different set of circumstances than when it comes time to deliver on the promise. Temptation is much stronger when it's in front of you than when it's an abstract notion.
Also, we are experts at rationalization, as exemplified by the excuses in the example above. That allows us to still think of ourselves as basically trustworthy...but on some level we do know that we're not great at sticking to our intentions.
DeSteno's suggestion for improving our chances of sticking to our intentions is to use technology, like apps that remind you to exercise or ask you to record everything you eat, for instance. One smiple app for this kind of reminder is a web tool called Joe's Goals. If you want to have an element of social reinforcement, 43 things is a good choice.
Reminders are good but can easily be ignored or rejected with the same kinds of rationalizations we're used to employing.
More powerful are the tools that include a penalty if you don't do what you said you would. For instance, you can specify that a certain amount of money will be donated to a political party or cause you don't like if you don't deliver. One of the most popular tools for this is StickK.
If you really want to ensure that you follow through and don't fib or rationalize, it's best to put the judgment of whether or not you complied in the hands of someone else...tricky at best, as it's easy to imagine this leading to arguments and broken friendships.
Here are some addiitonal tips that might be helpful:
* Tackle one thing at a time. Will power is limited and while today it might seem noble and exciting to start reforming three or four aspects of your life tomorrow, tomorrow it won't seem nearly as attractive.
* Apply the same chunking strategy that you may already be using to overcome procrastination. For example, if having a healthier diet is one of your goals, start by deleting one unhealthy snack from your diet. Once you're used to that, choose another small modification. (Note: there are some people who are more motivated by making a big change and find this works better for them--try one approach; if it doens't work, try the other one).
* Use cues to remind yourself of what you have promised yourself you will do. As well as using web tools and apps you can put notes to yourself on the fridge, or put your gym bag by the front door, or leave your manuscript file open on your computer so it's the first thing you see when you fire it up next time.
* Ask for constructive support from friends and family. Ask them to remind and encourage you to stick to your intended behavior.
Gotta go, I intend to spend the next couple of hours working on my novel...
(You'll find a lot of practical help in my book, Focus: Use the power of targeted thinking to get more done, published by Pearson and available from Amazon or your other favorite bookseller.)
There may be more tips in his forthcoming book, The Truth About Trust, although I confess I think it may turn out to be another book that actually would be a better long article.