I installed BetterTouchTool on mine, and you can configure an action to run when sliding anywhere on the touchbar with 2, 3 or 4 fingers. I set 2 fingers to volume control and 4 fingers to brightness and that works pretty well, no need to look. I also make it display the time and battery percentage at all times, which is nice to have when an app is running full screen. BTT isn't free, but it's pretty cheap, worth it IMO.
BTT is so useful it ought to be bought by Apple and incorporated in the OS. Throw in the top 20 used presets as checkboxes and be done with it. It's the first thing I install when I set up a Mac.
