I would start slow. Walk for 30 minutes everyday (not throughout the day, but all at once). After you do this for a few weeks, increase your time. After a little while, you should be able to seamlessly transition into using a treadmill, bike or elliptical for short periods of time, then longer as you progress. Most important, however, is your willpower. For some reason, when it comes to exercise, my will can’t be broken. I allow myself no excuses. Since I decided on my schedule, I don’t allow myself to miss the gym. There is no excuse, unless I’m feeling so ill that I can’t get to the gym under my own power. I’ve angered family members many times because they wanted me to break my schedule to do something with/for them. In a sense, allowing no excuses for yourself makes it easier. You are on automatic pilot and almost nothing can stop you from doing what you have to do. There’s no indecision or weighing of choices. You exercise because you have to. There is no other option.