I used to play as a King, but my emperor game seems to be going well now... but it's much tied to my OVERpowered Janissaries (ottoman UU)
I had a very though start, being stucked in a very difficult war against mongolian invaders for maybe 150 turns! (epic speed). but as soon as I counter-attacked with my first Janissary (+50hp when kills, recovers full heal in my game -becoz of a bug OR bcoz Fountain of Youth?-) I smashed him back
I also had another -bug?- which helped me a lot: Montezuma attacked me with a decent small army, I fought him back, then, out of nowhere, he offered me peace with all his money in exchange! I was just tracking his wounded units, but not even sieging his city... Gave me twice 1000+ gold which was huge at that moment
1 luxury less by map size is a great idea
religion bonuses can help a lot, in my current emperor game, at some point, more than half of my net gpt was from Tihe
I sometimes struggle with happiness, then have 30+

, it's kinda more fluctuation... a lot of my happiness is coming from unique resources from CS (porcelaine, jewelry, but also very rare -in my game- ivory, furs or dyes): if I lose two or three CS' alliances,
I could lose 20
happiness in once! (3 luxuries + 2 mercantiles)
Most of my money is coming from trade routes (about 400+ while my net GPT is "only" 250). It's a huge map, and I settled a big part of the second continent. But I only have two harbors on each continent: if enemy AI blockades two harbors, it could cut me 200+ gpt! I'm scared for my next attack...
to be short: seems a bit easier for me, but could be relative to two bugs? (Janissary OP and Montezuma giving to much gold for peace)