Plenty of tutorials on basic use of it on the web, you'd be surprised once you know some of the basics how easy it is to use really.
A lot of the technique in removing things using just the clone tool is just common sense, try not to repeat objects and try to maintain lines and any natural patterns along with matching lighting.
On the other hand I've used it for probably 10 or more years and there's still stuff I've never used or touched in it.