Using Photoshop generally means using a brush at some point, and not just for painting. Several tools within Photoshop also use a brush – Eraser, Dodge, Burn, etc. Here are some useful shortcuts when using a tool that uses brushes…
Click, let go and shift – click elsewhere in your document and you will get a straight line
Click and hold with your mouse button, then hold the shift key, and then move your mouse – you will be constrained to horizontal/vertical lines
When using things like eraser, dodge, burn, etc, Photoshop sees one stroke as mouse-down and mouse-up. If you just paint with one mouse down, and then let go, you will get one long stroke with one application of your effect (like with the dodge tool you will only lighten a little bit, not build up as you might expect).
So it is best to use short strokes, and let go of the mouse, short strokes, etc.
This means that you can also do multiple undos and so have a lot of control of how you step back, and you can see the effect build up as well.
Do not forget that all the tools that use a brush have access to brush shapes and so you can rub out and apply effects in any shape you wish – text, logos, etc.
Also, use the [ and ] keys to decrease/increase your brush size on the fly, and shift + [/] changes the hardness of the brush – very useful.
Let me know of any clever brush shortcuts you have come across!
