Get yourself a planner and mark the dates by which you want to achieve the various goals, such as a full hour of intensive training or the first two pounds to lose. As you reach them, put a check mark and set new goals as shown by Fitness and Nutrition Blogs.
Give yourself some prizes. If writing down the objectives is not enough, incentivize with prizes and discourage yourself with penance. For example, if you decide to train at the gym twice a week during the first month and you can, give yourself something you have long desired. Otherwise, give up something.
Set yourself realistic goals. Goals can only be achieved if they are realistic. If you have not been training for months, or worse, you have never set foot in a gym, do not try to train yourself every day, because you will never succeed and failure will make you discourage.