Thanks, but my answer was quite short. Too short in fact.
I usually start with making a copy of the background (original layer), and then I add another empty layer to work on. This way I always have the original open, and I can work with the copy, and whatever I heal, clone or paint happens on other layers, so it can be turned on or off, and many more things can be done.
Then I make shure that the 'use all layers" on the option bar is turned on. Otherwise I cannot clone as my layer is empty.
Then I try to do as much as possible with the healing tool, the patch tool and the clone tool. Sometimes, the area that can serve as source for the clone tool is so small that a repeated pattern is as good as unavoidable. That is when I use a small painting brush to paint in pixels. When you have selected the paint brush, you can set the size with the [ and ] shortcut (if you have an English keyboard that is, or if you can set your keyb to English. In the latter case: don't use the Shift-Alt shortcut as it is the cause of many problems!), you can use your numbers to set the opacity, you can use the Alt key to temporarily switch to the sample tool. This is very handy as you can at any moment, whilst painting, choose the colour with which you want to paint by just pressing Alt.
If your monitor allows for it, I also recommend opening a second version of your image (Window menu>Documents>New Window). You can leave this at 100% while you zoom in on the one you work on. This way you can always see what you are really doing without getting lost in the details of your zoom. If you are hesitant to paint, just turn your image upside down, and zoom in. The you only see pixels and patterns, not eyes and lips. In fact: even if you're an accomplished painter: this is a good technique to work on what you "see", instead of working on what you "know".
Have fun!