Hi, just got a deity domination victory with Trajan. (254 turns, Standard pangea)
I think military tech beelining is key. (completely neglect everything else!)
-Archery
-Iron working
-Machinery
-Gunpowder, Metal casting, Ballistics, Steel
Commercial and Industrial districts are key, too. And using the unit production policies correctly, of course.
At first I managed to be somewhat nice with my neighbours, having England on the same continent helps

Killed one neighbour with a joint war.
The thing is, they had a strong religious game (which I neglected completely in favour of military strength) and got monarchy and theocracy governments quickly. And from that point on they will hate you almost instantly on deity for having different governments and start declaring wars. My early crossbows and the strong legion won the game easily though.
I have to say, the AI seems weak. All attacks they mounted were really lackluster... I bordered on the coast, so that helped I guess.