The best advice is just; eat less, do more.
I've lost 7 lbs myself over the last 3 weeks and literally all I've done is cut down how much I am eating and walking more. I'm still eating shite, just less of it.
Depending on your weight, a 30 minute brisk walk every day will burn between 200 and 300 calories. Combine that with eating one less mars bar per day and that's a deficit of 500 calories compared to what you'd usually be. 1lb equates to around 3500 calories, so a 500 deficit per day will mean the loss of 1lbs a week.