How to destroy a base more efficiently in Starcraft 2

I know this is kind of a far fetch, but every once in a while I have a game where I'm destroying my opponent base while he is destroying mine, and it all comes down to who does it first. Of course if one of us gets a worker out and builds something far from his enemy's army this is all pointless. but assuming all the workers have died..

Is there a better way to destroy a base than just moving all your army in an Attack-Move inside it?

This applies in general but I think it's especially true against buildings since they don't attack back.

Make sure every unit is able to attack something. This usually means moving closer than max distance so the units in the back aren't fumbling around trying to get into range. (In army vs army, you'll want to do this if your army is bigger, but not if your army is smaller)

Against buildings that don't attack back especially, you'll want to split up your army to help with making sure every unit gets to attack something.

Doing the Stutter Step also help to keep moving towards other buildings as you attack. Stutter Step is where you either Move->Stop(to shoot)->Move->Stop or Move->AttackMove->Mode->AttackMove.

Normally this is used to kite units with shorter range, but it's equally effective to spend less time not attacking. The key is that the attack cool-down is ticking whether you're moving or standing still, so in the time between shots you should be moving closer to other buildings. With enough practice you can move and attack while getting the exact same damage output as if you were standing still.

All of these technique though are different ways (that can be used in combination) to minimize the amount of time spent not attacking, which is the ultimate goal.

Davy8's advice probably covers the main point (make sure each unit is attacking to its full capacity), but here are a few other ideas:

Terran bases:

• You can attack each building until it's in red health, then move on. They will slowly burn down.
• Watch out for buildings lifting off and scattering. You can prioritize buildings that can fly, and try to get them into the red before they're out of range.

Protoss bases:

• If you have Ghosts, you can use EMP to take out some building shields.
• It is sometimes good to go for Pylons first, as they have low health and if you can eliminate key ones so that important buildings are unpowered, they can no longer train units, etc.

Zerg bases:

• Focus fire is a little more important, as buildings will slowly regenerate health.
• If you can destroy the creep (hatcheries and creep tumors), buildings will start to lose health once they are no longer on creep.
• Make sure your units aren't wasting time attacking larva, which have 10 armor.