We know that a large number of London visitors come from the USA, and, unless you live in a big city, you will be more used to driving and less used to public transport, certainly on the scale found in London.
Bus travel is really great if you are not in a hurry. You get to see lots of sights in relative comfort. But getting onto a bus is not the simplest thing in the world if you are not used to it, and drivers are typically not helpful.
So, here are a few practical tips.