Everyone knows that by tapping a control group, you select all the buildings and units that are hotkeyed under that control group. However, did you know that if you double tap a control group, your main screen centers on the buildings and units that are hotkeyed?
This is especially useful when controlling multiple armies. If you have a drop in your opponent’s main base hotkeyed as 6, while your main army is just outside your opponent’s third base hotkeyed as 5, you can double tap the hotkeys to micro both fights (nearly) simultaneously! 55-a+click, 66-a+click, 55-retreat, 66-load up and get out of there. It’s so easy!
This tip also makes it useful to build new production structures nearby the majority of similar production structures. That way, when you add on an extra Robotics Facility next to a previous Robotics Facility, you won’t lose track of the new one. Simply double tap your control group to center the screen on your previously-hotkeyed Robotics Facility, find your extra Robotics Facility nearby on the screen, and then add it to the other hotkey. Instantly, all of your production is hotkeyed perfectly.