1. One must always  have cognotive control.  This means to always be aware of what you allow to pass through your lips. Don't allow yourself to slip back into old eating habits.
2. Do not give up your support group just because you have reached your goal. You didn't get where you are today without that support, what would make you think you could stay there without it.  These people are your lifeline, your sounding board, and most empathetic supporters that you have.
3. Don't go Hog wild.  Even on a "free day" moderation is the key.  Don't go on a food frenzy just because you are "allowed " to eat certain foods.  Seek balance in all parts of your life.
4. One must continue to exercise. This is a new way of life.  Exercise not only helps you lose weight, but helps you maintain it as well.  Exercise is a way to get your body stoked up to burn more calories. One of the advantages of regular exercise is that one builds muscles and lowers fat, and muscle burns more calories. 
5. Eat 5-6 small meals a day and never skip breakfast
6. Monitor your weight weekly.  A buffer of a couple of pounds is a good thing to have.
7. Maintaining is having a positive mindset.

And if none of the above seems to do the trick...Remember nothing tastes as good as being at goal feels!!!!