Emperor player also. I never go authority; I've accepted it simply doesn't fit my preferred play style. If I start next to one of the early belligerents (Songhai, Zulu, Aztecs, Mongols, Huns, Persia) I beeline military techs, build a formidable early force, and make sure cities I settle in their direction are in defensible locations. If I can steal settlers I will; it's only a matter of time before they declare war so if I can preemptively weaken them, I do.
Once we're at war I'll often remain at war if I'm in good position. Peacing out to allow them to rebuild and launch a new offensive is a suckers game. I'd rather keep harassing their cities and units while building my infrastructure; by this point I've already built my military units, they might as well keep busy.
Lastly, adjust to your specific opponent. As CrazyG mentions, Songhai's UU isn't as worrisome if he has no horses. The Aztecs are brutal in forests and jungles; avoid settling where they can use them.
Persia has been my most difficult early opponent lately; those Immortals are tough to counter. I've found beelining for Swordsmen to be the only reliable counter if I can't settle good choke points.