Adobe Illustrator Shortcut keys – Font: Size, Leading, Kerning & Tracking
Cmd + Shift + > or < = Increase/decrease font size
Opt + Up or Down = Increase/decrease leading
Opt + Left or Right = Increase/decrease kerning or tracking
Cmd + Opt + Q = Reset kerning/tracking to zero

This Tip is written in Mac  If you are using PC,

Cmd key = Ctrl key

Opt = Alt