Hi there!
I think that your question is going to have a lot of answers, because it really depends on the individual and what will work for them, and fit around their life.
Take a look under Diet Central. That's a pretty standard list of what most people around here are following.
If you'd like to do something that's free & easy... calorie count! There are a myriad of ways to do it, but you can even just keep a pen & paper around to write down your daily calories
I can tell you that for me Weight Watchers has worked wonders. I like the way the food program works. I like that they're emphasizing good health guidelines, and moving more, and I enjoy going to the meetings for group support.
If you've tried some things, you might know right off the bat a few programs that won't work for your life. However, you might see something that you think you'd be able to pull off. Take time to experiment.
Whatever program you choose, the one thing they all have in common is that they all require commitment for the long haul.
Best of success!