One thing that's often overlooked is the lighting. It's either a couple of feeble bulbs or some old and dusty fluorescent tubes. Upgrading those to LED tubes is one way to fix a dark and gloomy ...

LED strips can be cut to size, and most come with peel-and-stick backing for easy installation. Tiny LEDs encased in a long, clear, flexible PVC tube that allows the light to shine through.