Take Your Time
As you undertake a cloning project, the quality of the result is directly
proportional to the amount of time you put into it. Cloning photographic
details can be incredibly tedious work. The world has become well
acquainted with Photoshop magic, so never assume that no one will notice
your blunders.
Duplicate the Active Layer
The very first step to take when cloning parts of an image is to duplicate
the layer you’ll be working on (or to just work on a new transparent layer).
Realizing that you made a mistake so long ago that your “Undos” don’t go
back far enough to fix it is beyond frustrating. Keeping the original image
on a hidden layer gives you the flexibility to revert any part of an image to
its original state.
Be Selective With Your Tools
Each cloning tool has its strengths and weaknesses, as outlined above.
Never arbitrarily grab a tool and stick with it for the duration of a project.
Consider which tool is best suited to the particular area of the image you’re
working on. On large projects, no single tool creates believable results on
its own. Use two or more tools in synergy to achieve a realistic result.