This is a great thread! Lots of good tips. I think the most important one, though, is just finding what works for YOU. Most of us have been on a million diets or we've at least read or heard about all of them. I know all about the diets I'm NOT doing (low carb, no sugar, etc)--I've read the books, I've tried them, etc--and I know they don't work for me. They do work for some people, and that's fantastic.
Sometimes people get so caught up in their own diet plan because it's working and they think they have the secret key, but we have to remember that what works for us doesn't necessarily work for the next person. If I had to cut out sugar completely, I'd last about one day. If I had to cut out ANYthing completely, I'd last about one day. I have to have freedom -- my restriction is my caloric intake (WW points, but it's the same thing). For some people, they hate that kind of counting, and they'd rather do away with certain foods.
Try something and if you know you can't sustain it forever, dump that plan and try something else!! If the scale goes down or your clothes get baggy, you've found your own "secret key" to weight loss. The great thing about this message board is you can always find a group of people who are doing it "your" way, and you can read about other ways if you need to switch.