Basically, gaming mice give you more buttons to control the action in the game. Good gaming mice give you more ways to customize their action, they give better comfort, and they look flashy.They come with software that help you map different actions to your mouse buttons for each game you play.

They have  better optical sensors and settings, which are optimized for gaming. They are of course more accurate than regular mice.

Gaming mice are built to fit one or more of the three most common mouse grips, palm, claw, or fingertip, and thus they can feel more comfortable for your hand than a standard oval mouse.

The best gaming mouse: Razer DeathAdder Chroma (comfortable for extended gaming sessions, upgrade version of DeathAdder Classic, more sensitivity and color-changing RGB lighting)

The second best gaming mouse: Logitech G502 Proteus Spectrum (adjustable weights , many buttons for better control)