A good tour guide provides simplicity in planning and comfort by taking care of all the details for you. They will provide you with valuable information about the places you're seeing and the culture, people you are visiting. You can have private as well as group tours. But it is always a great way to meet new people and get your feet wet if you're new to travel or you have only a short visit time.
Our tip is, before visiting London, follow @londonguidecansu and get in touch with her. Cansu Aksit, is a liscened English, Turkish and German cheerful very knowledgeable lovely guide.