Some great advice in this thread. One thing that stuck out for me was to take things slow. I know there are plenty of people on this forum that have lost more weight than I, but I'm pretty good at it, and at least decent at keeping it off.
I dropped from 280 down to 190 over the course of a year and a half, and wow did it change my life. I cleaned up my diet one step at a time, and I slowly added exercise until I met my goal. The great part is that you don't shock yourself into hating your new diet or exercise routine, and as you see the results of each small change, it motivates you to make more small changes.
4 years later, I got an amazing girlfriend who likes to cook delicious but not so healthy foods, and a job that demands silly amounts of commitment from me. As a result, I am back to 230 lbs now, but I caught myself in bad habits before it was too late, and I'm going through the same process of eliminating bad habits and adding good ones one at a time.
This time around should be a lot easier And I've learned from my "slip" too, hopefully never to get cocky and allow such a mistake again.