Yeah, you don't make units, you make battalions.

Siege tanks are grouped with marines and firebats for protection, Marines and medics run with medics for assistance. Have your infantry out front. Move to a location, plant your troops, put your tanks in siege mode, rain hellfire down upon aerial defenses and approaching units so your Battlecruisers can come in with their Vulture and Wraith support to decimate a base.

It takes a village. You know, to destroy the other guys village. But still. Villages.