If you’re using one of the new Dell Optiplex 9020 (or similar Dell All-in-One), you can make some quick adjustments to the display to make your screen provide more accurate colours, while reducing the glare of the display.
To get started, right-click on your desktop and select Graphic Properties
Click on Display
Click on Color and adjust the sliders as picture: -20 for Brightness; 50 for Contrast; and 1.0 for Gamma
Then simply click Apply and close the window, and you’re done!