The patch tool is often a very underutilized tool in Photoshop. Hidden under the Spot healing brush and 2 other tools, the Patch tool is similar to a combination of the lasso tool and the healing tool. You select an area, click the appropriate button (source or destination- mine is usually on source) and then drag the selection to another area that has characteristics that fit your needs.
For example, in one of my photos, “Fall in the Hills”, the photo was dotted with houses and roads that didn’t add to the composition. I simply drew around the houses and roads with the patch tool and drug them into an area with trees. The result is no more houses/roads, that simple. The patch tool is often superior and easier to use than the clone tool, especially for large areas, achieving better results.
Another example, if someone has black rings under the eyes, you trace around the area that needs work on, select “source” in the Tools Option Bar right above the Tools Palette), and drag it to an another area of skin that has a more likely color. Make sure that the area you are dragging to is blemish free, as you will pick up any blemishes that are in the destination area.
The best way to see how this tool works is to practice with it. Easy to use, you can cut your work time way down by using this over the clone tool. I rarely use the spot healing tools any more as well, finding this faster and easier. For most general use, it is easy to use. It takes a little more practice to use when there are lines in the area that needs to be fixed. You must drag it to a destination that has the lines at the exact same angle.
The patch tool goes all the way back to Photoshop 7, and has been improved on in the newer versions of Photoshop.