I covered single-point perspective in a previously issued page. Two-point perspective just develops the principle. It’s essentially the subject itself which determines how many “points” you need: you may be able to describe a simple street scene in single-point perspective, however a street corner……..is another matter!
Here are a couple of explanatory videos:
Here’s a link to an example reference – you could use this (or indeed any cityscape) in order to practice the concept. The reference has some limitations and in fact there are one or two perspective problems……perhaps you can spot a few!
Here’s two-point perspective applied to a real photo.
Happy vanishing points!