Eat a good breakfast. Cereal with semi-skimmed milk (that white, watery #### they call skimmed is rank), a slice of toast, fruit juice and a yoghurt. That will stop you feeling hungry too early in the day, and prevent you from snacking.
Take a 'normal' lunch, whatever that may be, but have a slightly smaller portion than normal.
In the evening, eat a light meal. Your body doesn't have enough time left to effectively burn off the calories you take on board at this time, unless you are particularly physically active. A simple salad, or even a fruit salad should stop you feeling hungry past bedtime. Make your own - don't buy any of that tinned rubbish.
Keep as busy as possible during the day, as boredom tends to lead to snacking which can be a real problem preventing weight loss. Try to avoid fatty foods and snacks. Limit your portions to a bit less than you would normally eat. Don't eat or drink high sugar content products either, and if you are a smoker try to give it up. Get your doctor to assist.
Additionally, you need to exercise if you aren't already. I hate jogging, but cycling I find much easier and as such, much more enjoyable and therefore ultimately more effective. Walking is good too, but it needs to be at a reasonably brisk pace, or strenuous to be effective. Hills or repetitive stair climbs are the best.