London is a beautiful and enormous city that requires a bit of planning if you want to see as much as possible from its attractions.
The most important thing everyone who visits London has to have is a proper map that shows underground lines. As tube is the easiest and fastest way to get from one point in the city to another. You can also find out about bus routes as it is usually cheaper way of travel around the city. Why not consider exploring London on foot keeping in mind that many of the city's major attractions are within walking distance from one another.