The sky is a free slideshow you can view from any bus stop and, thinking back, I guess I have been a cloud watcher my whole life.
Since the sky often displays a huge range of brightnesses, clouds can be difficult to photograph well but it's easy enough to learn how.
Click on the Read More for an image gallery.
Cumulus clouds are particularly challenging, and unless you take care your photographs will burn out the bright cloud tops.
My top tip here is to underexpose your shot by at least two stops. Then in the software you can readjust the overall brightness while still retaining detail in the shining tops.
Any decent processing software will contain masking tools or gradient tools. I use both Lightroom and Capture One to do this - it's not cheating!
The sam technique can be used to stop the bright areas around the rising/setting sun from burning out. Keep an eye on the histogram as you work.