Make "Mile Marker" (aka. mini) goals
and reward yourself for achieving them. Whether the thing you measure up against is dropping a dress size... x% Body Fat, or just keeping with your plan for more than yy days... pat yourself on the back when you do it. It will help you to continue.
Nothing is more daunting than a single far off goal, so it is important to see yourself making steps towards it, and making mini-goals helps with that.