Share Your Best Practices

Don't starve yourself.
Log everything even if you have a really horrible day
Figure out how you got where you are now and what you need to do to permanently change to never go back there
Find a good fitness program and stick to it

Consistency and patience mean more than anything else

P.S. Stay the heck away from the fad diets and diet plans that eliminate entire food groups. They aren't necessary and the overly-restrictive nature of them can lead you to failure.

Log everything
Try not to eat food from a box, can or celophane
Eat yummy food
5-10 minutes of exercise a day is not enuf but it is an IMMENSE improvement over -0-

I'll just echo some other things already said.

1. Log it, no matter what it is , one hersey kiss, log the thing in!
2. Make small goals in addition to your big ones. Write them down, put them on the fridge, the bathroom mirror wherever you can be reminded you made a goal.
3. Remember it's a process, it won't happen overnight, it won't happen in a week. Know that you are making a change for the good.
4. Check the forums. I swear, the forums have been one of the reasons I have been successful this time. The support you get and just read is an amazing motivator.

Good Luck! You can do it!

I have to agree that I have been trying to pre-log as well because it helps me stay on track mentally and if I have physically logged in what I will eat for the day, I tend not to stray as much. Same with excercise. If I log it before I have done it then for some reason, it gives me more motivation to do it! Writing things down for me helps me actually do them. I also keep my log up all day at work so I can track right away as opposed to doing it later and forgetting! Trying to be as proactive as I can with using this site!

What everyone else said, plus:

1. Don't set time limits for yourself, like "I am going to lose XX lbs by XX date." I have learned that even if I do everything "right", I may not see a loss at all (or even a gain) for three weeks in a row, then in the 4th week all the weight will fall off. Just because your behavior is consistent doesn't mean your weight loss will be. I almost gave up a few times at the beginning because I didn't understand this.

2. If you can, invest in a heart rate monitor so you can figure out how many calories you burn during workouts. This helps if you are going to eat back your exercise calories (I usually eat back half) and it gives you an idea of how hard you need to workout to "burn off" something. For example, I know that to burn off one shortbread cookie from Panera, I have to do a tough Jillian Michaels DVD for 40 minutes. Is it worth it?

3. The community really helped me a lot. I've built a really great list of friends on here and we motivate each other daily through good days and bad. They have often kept me from giving up. The message boards are good when I'm bored at work, haha. I've learned a lot from them (like more protein is good, and women won't get bulky by weightlifting) but there's also a lot of nonsense and mean people. Just gotta know how to sift through them. I usually keep MFP open all day at work (and hide it when the boss comes around!). I use the app on my iphone when I'm at home or out and it has made a HUGE difference. The app is essential.

Good luck and feel free to friend me!

Some of this has been said already, but here's my 2 cents:

1. Log everything! Even small bites, cheat days, and weekends. This helped me realise just how much my weekends were undoing all my progress during the week.
2. Eat! Don't starve yourself. You need fuel for those workouts. (Plus, when I don't eat enough, I'm SUPER cranky!)
3. Exercise! Since I have a low metabolism, I really need to exersise so I can eat more and not feel like I'm starving.
4. Pre-log your day. I typically pre-log my breakfast and whatever I brought to work for lunch, so I know how much I have left for dinner, or if I can get away with a small dessert.
5. Set small, achievable short-term goals in addition to your long-term weight-loss goals. For example: by Valentine's Day, I aim to fit in the next-smaller pair of pants I have hanging in my closet. This makes those long-term goals less daunting. Also, document your progress and recognize/celebrate what you have achieved so far!
6. Focus on calories in / calories out to begin with. Once you feel like you have a good handle on that, you can start paying more attention to macros (protein/fat/carbs), other nutrients (fiber/sodium/sugar/etc.), clean eating, or whatever other nutritional goals you may have in mind. But if you try to jump into all that at once, it can be overwhelming.
7. Find someone IRL to be accountable to, and keep them up-to date. For example, I'll sometimes tell my hubby that I've been going over my calories, and I'm not allowed to have any XYZ that day. Then if he sees me going for it, he'll yell at me.