I agree with both Heidi and Mmc that posting here and becoming friends with all these like-minded beachers has been the greatest motivation for me. I post every day no matter how I'm feeling and would highly suggest that. I've found that even when I have an encounter with unplanned food, it's much easier to get back on track when I get back to 3FC immediately. I'm also an advocate of sitting down here first thing in the morning which helps make the rest of the day a priority for eating on plan.
I had lost a substantial amount of weight on my own before I started SBD, but started regaining. I made myself a firm commitment to a clean P1 and 6 months OP. The clean P1 got rid of cravings and the 6 month commitment got me safely through some ups and downs. At 6 months I had the tools to keep going.
Best wishes! Jump in with us on the daily thread. It looks overwhelming at first, but you'll get to know everyone and I think you'll find an incredible base of support.