Many times, we want to erase part of an image and we don't know how. That becomes a problem. Well, let me tell you that that won't be a problem anymore if you learn how to use this tool.
In the following image, we want to erase the lady's silhouette.

Select ((Clone Stamp Tool)) and choose any brush size (the hardness will depend on the image). Generally, we use a medium brush with a low hardness so that you cannot see the marks of the area you cloned. So use size, 110px, hardness, 120%.
With ALT pressed, click the area you are going to use to substitute, in this case, the sky. Once you have done that, stand in the woman image. What you are doing is to cover part of the image with part of the same picture. Quite an interesting tool, huh?

You have to release the mouse every now and then so that you take the heaven area again.
Abra Cadabra! The woman is gone!.
