While the details may be more complicated, losing weight in general is fairly simple. It is calories in vs calories out. So an easy way to lose weight and keep it off is to incorporate small changes in your diet and add a little bit more exercise into your regimen. Instead of getting a hamburger, get a salad instead. And instead of parking near the office, you can park further away and even just that little extra walk to your work will have a great impact without making drastic chhanges that you may not be able to stick with for a long period of time.
The key is to make small changes and once you adapt to the new change and it becomes a habit, make another very small change.