You can also use the Quick Mask option to make selecting areas even easier. First, double-click on the Quick Mask button to bring up the options panel, and click on Selected Area, then click OK. This makes the area you paint over using Quick Mask into the selected area rather than the masked area, as is normally the case.
Next, choose the Paintbrush tool, and set its tool options for a small soft-edged brush.
Using the brush tool in Quick Mask mode, paint over the area that you want to repair. When you’ve covered all of it, click the Quick Mask button again to return to normal selection.
The selected area should now be surrounded by a marquee. Select the Patch tool, and use it to click and drag the selected area just as you did before, to an area of clean pixels. When you release it the tool will copy and blend as usual. Again, use CTRL+D to de-select the area when you've finished.
Use the Patch tool in conjunction with the Healing Brush and Clone Stamp, and you will have a powerful array of tools for retouching any picture quickly and effectively.