There are many types of clouds than we didn't have room for in this lesson. You might have to do some research to identify a cloud that you see. What you're really learning from doing these forecasting tricks is observation. Observation is a word for carefully watching things and what they do. An important part of forecasting, or any science, is observation.
Meteorologists observe the weather when they're making a forecast.
Observation is a good skill to have for whatever you do, because it makes you better informed about the world around you.