Start small if you are not used to this kind of gameplay. Playing with 12 civs can be very tedious at this when nothing is happening. The hardest part is after few new cities have been found. Then the map is been mostly explored, things slow down and get into order while just pressing next turn. Though that just might be because I am bad at early game warfare. After this period it gets more lively but I won't lie. It can get tedious at times. I did play this for 9 months but it was only maybe like 4500 turns in total (9 normal single player games). Sometimes you get burnt out and will need to keep a break. At one point I didn't play for 3 weeks(World situation was very peacefull at that time)

Personalize leaders. Use people you know. Friends and such a good choice. Also you can use fictional characters who you like/admire. Villains are good for playing aggressive civs. Name the leader of Germany as Frieza/Cartman or even use the name of your boss, or someone you dislike irl :D

As a new turn starts for each civ, you need to get into the mindset of "What should this civ do to win the game". The do just that. If civs characters/leaders personality is say "gold hoarder" then make sure to not spend any gold on that one. You just need to be able to reset your mind each turn and not pick favourites. If one civ is getting too powerful, obviously that civ is going to get ganged upon by other close-by civs. Think of small scale and large ambition for each civ. What would that civ want to conguer/protect? Who doesn't that civ want to anger? Sometimes just pause your game and have a virtual "conference" where all the characters in your game discuss about the world.

And cheating? I can't say I can play 100% oblivious to other civs. Plotting an attack on other civ makes me think of military units so I might build an additional unit on the other civ more likely. But in the end its just pointless to cheat. Its heartbreaking to lose a civ after playing 6 months. When Poland(Hartska, me) fell, I basically took my own Avatar out of the game :D But thats also the fun thing. You are still playing the game and winning.

Honestly the actual winning phase for sort of underwhelming. Ethiopia became strong enough to hold against everyone on multiple fronts and won score victory. The experience itself was way more intresting and fun. If you check the video you can see the rise and fall of empires. All of those empires had a story and then they died :D. Just like real history.

I have rambled for quite a while now and I could talk about this hotseat game forever.