Galactic Empire/Space Opera Guide

Big. Enormous. HUGE!!!

That is the key to things classified as Space Opera. Enormously huge. Empires with thousands or even millions of member systems. Trillions of citizens. Gloriously advanced technology that leans heavily into the hand-waving magic of such things, like a device that lets you talk instantly to anyone, anywhere in the galaxy. Warp drives or hyperspace that lets you get to the far end of the galaxy in weeks or months, instead of generations or centuries.