cloning using layer masks!?

[UUilliam]

to show what you are painting press Q to enter quick mask mode
that will make what you paint red, to end it, just press Q again (but you will have to change to fill bucket and fill the selection doing it this way.)

 

[Peano]

When I select a paintbrush it doesn't actually show on the picture though, it just shows on the small thumbnail on the layers palette. Is there a way for the paint to show on the actual picture so I can see what I'm doing?

The paint (black or white) doesn't show on the image. What you see is the effect of the painting. If you paint with black, it conceals more of the cloning. If you paint with white, it reveals more of the cloning. It's as though you're erasing and "un-erasing" the cloning -- except it isn't really erasing. It's covering and uncovering it.

 

[UUilliam]

another thing, dont think of the mask as a paint tool

it is another form of eraser tool but better, I never use the eraser, I always use the mask tool as I can always undo / add bits back in.