• Set up a key command to toggle the Calendar List sidebar, so you can easily get it out of your way when you don't need it.
    System Prefs > Keyboard > Shortcuts tab > App Shortcuts > add two shortcuts:
    1. Application: Calendar; Menu Title: Show Calendar List; Shortcut: ⌥+.
    2. And the same thing, but with Menu Title: "Hide Calendar List"
  • If the text in your events are being cut off, for instance in Week view, you can actually adjust the text size a bit smaller using ⌘ + minus (-) or plus (+).
  • If you have more than 7 calendars like I do, then Apple doesn't provide enough distinct colors in their presets. Here are four more that work well: a nicely contrasting pink, a gray, white, and black. Another one that works pretty nicely is a much darker or brighter red than the default red. If you need even more, you could use Kenneth Kelly's 22 colors of maximum contrast, or this tool, or this other tool for generating distinct colors. Here's a couple examples from those last two.
  • Also, just know your shortcuts.
    ⌘T goes to Today, probably my most used shortcut in Calendar.
    ⇧⌘T goes to a specific date.
    ⌘1,2,3,4 toggle to respective calendar views.