welcome back...I find coming here helps me stay on track too
there's alot of great advice around, but I believe it is calories in and calories out. alot of plans hide that you are cutting calories usually by cutting food groups. I don't like counting calories everyday, it gets tiring and I'm not sure I want to count calories everyday for the rest of my life.
what I've been doing is playing around with some meal plans (fitday, and people have recommend sparkpeople.com recently) and count them for a few days to get an idea how much I should be eating and have been sticking to that. I try to make healthier choices when going out to eat lately. I find when I'm eating healthier foods I actually go under my calorie count goal.
I try not to feel too bad if I do slip up..and just get back on plan right away, the next meal, same day.
keep coming back here, it really does help to have support and know you aren't alone!