I have been looking around on Google for practice photos for the clone tool, but haven't found any good so far. The thing is that I am taking a paid course for Photoshop, and I have missed a couple of classes and now my instructor is angry at me for not being fluent with the clone tool. I'm new, so any kind of help is hugely appreciated!
Ask your instructor to explain it again or to recreate a practice session for you ,you are paying him for something he cant get away till u don't understand or practice the things properly,ask him 10 times 20 times just don't afraid of anything go ahead....
For your practice i rounded up some tutorials, you can work on there images too :
Hope this will help....
Try Mac Desktops. The link goes to the "Landscapes — Nature" category. Find something with lots of trees. Clone more of them.
If those don't inspire you, browse through the category links at the bottom of the page. There are thousands of images at the site; something will work.