The psychology behind this is that we humans often make a much bigger deal out of something that actually isn't that hard. The key is just to get started!
Especially true of working out. Sometimes you feel like it's the last thing you want to do and would rather "start tomorrow." Tomorrow never comes because it's now today, so starting today is what makes all the difference.
Step two and making yourself accountable is a brilliant and often overlooked strategy. If you know that you will owe someone if you don't do something that should motivate most of us to do so. The larger the amount you'll have to give, the more likely you are to follow through with your goal.
This can also work in reverse. If you want to help a friend, you can give them some positive reinforcement by taking them out and doing something they enjoy if they reach a certain goal.
You're full of helpful practical tips @sirwinchester. It's no accident or luck that you have been successful. I find that the harder I work at something the more "luck" I have. I build my own luck through hard work :)