I think one of the keys for that is to make changes to your lifestyle that you can maintain over your lifetime. Rather than looking at it as something that is temporary, like a diet, making lifelong habits will help. I also find that using SparkStreaks to track my progress with my goals helps keep me consistent with those habits.
To help you get started again, I would recommend trying at least one of the tips in this article: www.sparkpeople.com/resource/motivation_ar
To help keep you from getting overwhelmed with everything, try focusing on at least 1, but no more than 3 goals for a week. They can be something as simple as tracking your food, drinking 8 cups of water each day, etc. Choose what works best for you, but you don't have to do it all at once, nor do you need to be perfect.
You CAN do this!!