Cutting out the crap from your diet is the best place to start. Just remove all temptations from the cupboards then its easy. If you're peckish a bowl of cereal will fill you up. Drink lots of water, the flavoured stuff will do if you find plain too bland. I drink 1.5 litres every day without fail, think of the calories you'll burn running back and forward to the toilet too

I don't follow any type of diet, I just don't eat sugary/fatty crap, works fine for me. As others have said don't overdo the exercise at first or you'll put yourself off for good, build up gradually. Road cycling is my thing, nothing burns calories like pounding out several hours on the bike, just think how good you'll look in lycra once the pounds are shed

Watch out with running, no point knackering your knees, take it easy on soft ground if possible. Just find something you enjoy doing, there are no hard and fast rules, brisk walking is a good way to start. Good luck anyway, you will feel good once you know you're in control of your weight/fitness and not the other way around.