I have lost 2 stone [smug emoticon] but could do with losing another one!
This is what I did...
Avoid all sugary foods (hard at first but you soon get used to it)
Pile the plate high with low cal veg and only have very small amounts of sauces, gravy etc
Goes without saying that you should avoid fatty food such as pastry, pizza, sausages, but fortunately for me I'm not a great lover of that sort of thing.
Take more exercise (usually go on friend's cross trainer twice a week, ride once a week, walk more, cycle with kids when I can eg 22 mile ride last week)
Stop drinking alcohol during the week (I was having 2 or 3 glasses of wine per night)
Don't forget that very small differences can affect your weight greatly over time - there are about 3800 calories in a pound of fat, so you haven't been a pig to gain weight - just 120 extra calories per day will add a pound in a month! Luckily the reverse also applies - a small reduction in calorie intake together with a little extra exercise will allow you to lose a couple of pounds each month, which is far more likely to stay off than sudden weight loss from strict dieting.
Good luck, everyone!