You can use the following shortcuts with all tools which use the brush settings, such as the Brush tool, Eraser tool and Dodge tool:
Increase Brush Size
.
Decrease Brush Size
,
Increase Brush Hardness
Shift + .
Decrease Brush Hardness
Shift + ,
Increase Brush Pressure
Ctrl + .
Decrease Brush Pressure
Ctrl + ,
Rotate Brush Clockwise
ALT + .
Rotate Brush Counterclockwise
ALT + ,
