How do you stay on track?

I seem to do well for say 6 months, lose my steam and then revert back to my old ways. I'm sick of playing this yo-yo game. :explode:

There are a few things *short term* that help me, such as logging my food, hiring a PT, making friends who also are trying to eat healthy, etc.

So, I just wanted to pick your brains about how you manage to stay on track long term with attaining your goals.