Congrats on the weight loss! You've already beat a lot of odds just getting to where you are now. That's incredible and you should take a bow. : )
I find that so much of losing weight / keeping up good habits takes place in the head first.
If I start to dip into the doldrums, I peruse the Woo-Hoo boards, or the motivational section on Daily Spark, or read success stories / watch success videos.....all those seem to pump me up.
I think psychologically, it's just good for our minds to read / see others achieving what we want to achieve. It shows it can be done.
Another thing: encourage & cheer on other members (on the Woo-Hoo boards, on their Sparkpage, etc). Participate in their success. We all like encouragement & high-fives, and by giving those, you reinforce the positiveness of this whole (never ending) journey.
And if this journey is forever, you've got to make it positive in order to sustain it!
Good luck to you!