Brush - Adjusts the size of the clone tools capture and paste area.
Mode - There is a dropdown list with too many options to mention, I always keep it on Normal, but by all means experiment, the tools operation is the same.
Opacity - This sets how opaque the applied sample, for total obliteration set this to 100%.
Flow - This is the opposite of Opacity, it sets the density of the captures sample, sometimes it is wise to not set this to 100% if a gentle blending is required from the clone. Experiment here.
Align - When ticked the capture area moves in unison with the deposit area, if Align is left un-ticked the capture area if fixed and the same sample is pasted where ever clone circle is placed and the left mouse button clicked.
Using the clone tool.
1 )Select the Clone tool ( looks like a rubber stamp) from the tools window.
2) Set the brush size to the desired area that has to be cloned, the size is selected from the dropdown list, hard or fuzzy edged brushes can be selected, I usually use fuzzy edged.
3) Leave the mode as Normal.
4) Set the desired Opacity and flow, a bit of experimentation may be required here, it all depends on exactly what you are trying to achieve. Opacity & Flow @ 100% totally covers any object, but can leave a visible circle where the tool is applied, so sometime it may be better to set them as 50 or 75% and use multiple mouse clicks.
5) It is normal to have Aligned ticked.
Using the Clone tool to remove an object from the photo.
The clone tool changes the mouse pointer to a small cross. Hold down the Alt key and point this cross to an area on the photo close to the object that you are trying to remove and click the left mouse button once to capture the sample. The mouse pointer will change to a circle, (according to the Brush size), place this circle over the object that has to be removed and click the left mouse button, this will paste the captured area over the object that is to be removed. Dependent on the opacity and flow settings the clone may obliterate the object straight away or may need more that one try. If you have the History window open, Clone appears in this window each time the mouse button is clicked, if you make a mistake, you can either point the mouse pointer further up the history list of clones or go to Edit > Undo.
Copying an object from within a photo to another place in the photo.
Use exactly the same cloning procedure as above but ensure the Brush size is large enough to cover the object you wish to copy. Hold down the Alt key and place the cross in the centre of the object to be copied, click the left mouse button. Place the circle where you want the captured object to end up on the photo and click the left mouse button again. Remember a certain amount of the background around the capture will be transferred; this may look a bit odd. Where only the object is to be copied use one of the lasso tools, copy and paste the lassoed object, the magnetic lasso is best.
The Healing Tool
The Healing tool selected from the tools window, acts in a similar way to the Clone tool, it is best for correcting blemishes within a plane background part of a photo or cleaning up imperfections in skin when photographing people. The tool captures an area next to the imperfection and pastes it on top of it, but Photoshop blends together adjacent pixels around the blemish blending it away.
