InvisibleStalke
Emperor
Also, other tips I had forgotten but this game brought to mind. Not that you probably need them, just doing a brain dump here.
-- pre-build all the theatres, temples, and colosseums you can. I had over 15 spare happiness in most cities before the big war even started. This was a huge speed boost because I didn't have to slow down in the slightest. In fact, I stopped drafting/whipping because it became overkill. I had SoDs of musketeers leapfrogging cities to go and hit the next one.
-- I made full use of the good old Globe Theatre. My GP Farm didn't churn out GP. It churned out musketeers.
-- I also remembered (thankfully early on) to click emphasize food in my drafting/whipping cities. This has a big impact in keeping my cities from going down to low pop too quickly. In addition, I was running a CE so emphasize food also meant emphasize commerce, for the most part, which was ideal.
Wodan
Good tips there.
Pre building the colloseums would have definitely helped - I stayed in slavery longer than I probably should have to whip them. Prebuilding barracks is also a good idea - better than temples when you are in Nationalism. Honestly I wasn't expecting war weariness to mount up as much as it did - I miscalculated that Cyrus would vassalize to Peter and I missed a city he had set on an island so when I took out what I thought was his last city, it wasn't and the war weariness stayed.
My Globe Theatre was my whip/draft central. Its pretty powerful on Epic when your military cities are building a unit every 4-5 turns and your Globe Theatre city drafts one EVERY turn. I like to run the population up as high as I can in advance - think of it as banked production. Then switch to nationalism and draft away. I also liked having a great general settled in this city so I got a promotion - which meant with aggressive I could draft pinch riflemen immediately.
Its also good to have a few small cities for drafting. A size six city with fast growth can be drafted maybe every five turns which is equalling your production cities. Because its so small it can afford the draft unhappiness.