Getting started is often the hardest part of losing weight, as most people don't know what approach is the best, especially with all the options out there! In my experience as a personal trainer, I have found that the easist way to get started is to decide exactly what it is you want to achieve. This might sound obvioius and I can hear you saying "well I want to lose weight!", but having a clear, defined goal helps wonders. The best goal is a specific one, that comes from deep within and has sound reasoning behind it. The goal needs to be about your lifestyle and you as a person; one that enhances your quality of life and self esteem. You may have set goals before that sounded something like; "i want to lose weight for my wedding", or "I want to lose 10kgs for my birthay party". This is not the approach I recommend, as it encourrage short term compliance but results in long term failure. Most people who lose weight in this way rarely keep it off after the milestone has been reached. These type of goals are good "stepping stone" type ones, but try and come up with one that will encourrage long term adjustments to your liferstyle. After you have a clear idea of what you want to achieve, the next step is coming up with a plan for success. Part of this process is identifying what is causing you to keep weight on/gain weight; identifying errors in behavour and daily lifestyle then gradually making changes that you can stick to forever, not just for, say, 10 weeks. I have found this the best approach rather than going on a "shake" diet or something similar. Sometimes it's not even what you are eating that is the issue; things like lack of sleep, excessive life stress, not drinking enough water and skipping meals can cause weight gain too.
Have a think about what I have said, and if you would like some mroe information, feel free to post a reply