You’ve been able to colorize text in Stickies since at least Mac OS 10.1, but did you know that you could save your favorite colors and apply them with just one click? (Obviously, I’m hoping you didn’t or it really kills this tip.)
To do so, just highlight a word, then go under the Font menu and choose Show Colors. When the Colors dialog appears, choose the color you’d like. Then, click-and-hold in the horizontal color bar up top (where the color you’ve created is displayed), and start dragging slowly — a tiny square will appear under your cursor. Just drag-and-drop this square onto one of the white square boxes at the bottom of the Colors dialog.
This saves that color for future use, so when you want it, all you have to do is click once on that square (no more messing with the color wheel). This is a great place to save commonly used colors like red, solid black, white, etc.