Set a time. Put it in your calendar. It is an appointment, an important one, and you can't miss it. If you don't feel like it, tough, you have to go. You can't just cancel appointments without a good reason, it's rude! Put your shoes on and walk out the door when you need to be at your appointment. When you get back put a gold star on your calendar. Repeat the next day. How many stars in a row can you get?