Magic Wand Tool

As Simple As Photoshop > Tools > Magic Wand Tool

The Magic Wand Tool selects similarly colored areas:

In the Toolbox, select the Magic Wand Tool.
On the Options bar, set the tool's options:
- Tolerance defines the tools sensitivity. The higher value you set, the wider areas are selected.
- Contiguous forces selecting similar colors only in the adjacent areas.
- Anti-alised softens the selection edges. It is set by default.
- Use All Layers makes the Magic Wand to select likewise colored areas in all visible layers.
Click on the image with the Magic Wand Tool to select an area.

While the New selection operating mode is chosen on the Options bar, you delete the existing selection by making a new selection.
To add an area to the existing selection you have either to choose the Add to selection option on the Options bar or to hold down [Shift] key while clicking.
To subtract an area from the existing selection you have either to choose Subtract from selection option on the Options bar or to hold down [Alt] key while clicking.
To intersect a new selection with the existing selection either choose the Intersect with selection option on the Options bar or hold [Shift+Alt] keys while selecting.
While the New selection option is chosen and the cursor is within the selected area the tool looks like this and can move the selection (ie. borders of the selected area and not the image content).
You can also move the selection using the keyboard cursor keys.

* Layers explained in detail in The Skills
** Selection techniques explained in detail in The Skills