One more tip for using brushes efficiently: you can also change the size of your brush using the bracket '' keys instead of changing the size via the slider in the upper left of the interface.

If I'm ever unsure exactly how I want my brush to be set, I can toggle opacity quickly with the number keys while hitting 'Command + Z' here and there to undo anything that didn't work out. Aside from the time you simply save with this shortcut, it makes testing out opacity settings a breeze. Simply click on the layer and type in the number. You can also quickly set layer opacity in the same manner. If you need an opacity number lower than 10, say 5 percent, type the '0' then '5' key in quick succession. Since your non-mouse hand is typically resting on your keyboard during editing, this takes a fraction of a second each time. If you'd like to get more specific, you can type out '44' for 44 percent opacity. For example, simply pressing the '4' key will set your brush opacity to 40 percent. Anytime you need to change your brush opacity (which could be a hundred times a day depending on your needs and workload), just punch the desired opacity percentage in. The presenter dropped a tip that I jotted down in my notebook, and I have used ever since: Don't waste time with your brush's opacity slider in Photoshop. I didn't expect to come out of that lesson with a nugget of information that would save me seconds per image, which would amount to minutes per day, which in the end, adds up to countless hours of editing time. As that presentation proceeded, the presenter switched from his approach to photographing portraits out in the field to sharing his post-production process. A few years back, I attended a seminar from a successful musician portrait photographer.

Photoshop brush size shortcut