I'm not sure this is perfect advice. For one thing, speaking as a person who enjoys conversation, it can often be deeply uncomfortable when a random stranger tries to start a conversation. I made accidental eye-contact with someone on the subway today and then had to have a conversation about the weather which interrupted mildly productive thoughts.

I agree that in the contexts of school and work this sort of thing might be acceptable. One has to think about the fact that the very worst that happens is that the person indicates they don't want to talk.

One thing I do use as a conversation starter is if someone is holding a book that I've read (in which case I'll comment) or a book I have not read (in which case I'll inquire about it).