As well as the answers given, if your Mac has a Touch Bar, you can customise it to include a toggle for Do Not Disturb in the Control Strip which is (nearly) always visible. Of course, you'll have to give up one of the other functions from the Control Strip -- the defaults are brightness, volume, mute and Siri. 

[![Screenshot of Touch Bar customization pane with the Do Not Disturb option hand circled in red.][1]][1]


  [1]: https://i.sstatic.net/lL8z7.png