I see a lot of tourists make the same mistakes when they visit London, my home city.ShutterstockI was born and raised in London, where I've seen tourists make mistakes and waste money.Instead of spending a ton on taxis, navigate the London Underground or walk (when it makes sense).Prepare for all types of weather, and don't forget to order a Sunday roast at a local pub.As someone who was born and raised in London, I've seen tourists make their f…