Here’s a quick tip that will increase your productivity with Photoshop Brush Tools.
When you have a brush selected in Photoshop or Photoshop Elements, you can use the bracket keys to quickly change the size of the brush. Pressing the Left Bracket [ one or more times decreases the size of the brush you are using, while the Right Bracket ] key increases the size of the brush.
Holding the Shift key while pressing the bracket keys softens or hardens the brush tool. Try this technique on a round default brush. Press Shift + Left Bracket one or more times to soften the brush edges, or press Shift + Right Bracket to harden the brush. You can watch the brush tip change in the Options Bar as you press the keys on your keyboard.