Quickly change the brush size (without using the slider)
When you’re using any tool in Photoshop that uses a brush such as the Brush itself, Eraser, Dodge, Burn and many others, you can change the size of the brush using a keyboard shortcut rather than having to use the size slider. This fast and easy shortcut can save you a lot of messing around.
To change the size of the brush for any tool that uses it, press the opening square bracket key ([) to decrease the size of the brush and press the closing square bracket key (]) to increase the size of the brush.
Notice from the top image to this one the brush has increased in size (I pressed the keyboard shortcut ] to do this) and I can easily make my adjustments without having to mess around with the brush size slider.
Photo credit: © anitab0000 freeimages.com
(Photo by: Jorge Vicente)