How on Earth are you supposed to do this? I've tried everything.

I had four of the other AIs friendly with me and the other two were pleased.

Yet only ONE of them voted for me, the other all voted for the other guy!

How can I win it? (the honest way, not the way where you just vassal everyone)

They need to be Friendly to you (i think there is also a threshold like +10 attitude or something). And they need to like you more than the other guy (if they are friendly to both -> bad).

Another possibility is collecting Vassals. Those will vote for you (Unless they are the other Guy).

That said - i never won [un-cheesy] diplo myself. Seems to much of a hassle pleasing all those unthankful jerks.

yea, diplo victory without vassals is tough, and I would say nearly impossible under certain situations. I've done it on monarch a few times without warring or making vassals, but it takes a super strong religion, and the key as I see it is that the 2nd place runner-up needs to be a warmonger or just generally a turd that never gets along with most neighbors. Of course there is the struggle to keep a majority of civs friendly with you, and at the same time keeping population high enough to get a large number of your own votes and remain firmly in first or second score-wise. All that while maintaining enough defense as to not become the AI's scratching post... But in the end, diplo victories are one of the most satisfying for me!

here is a few tips and surely you'll win. I think you have to have +11 in order for AI to vote for you. In my experience it is very hard to win the diplomatic win if you play peacefully. There are few reasons for this. As you are trying to please few of the AIs others hate you more, and if you don't conquest any AI your voting power isn't very good when voting starts. Here is my strategy. I usually win it by 1900(up to monarch). I always try and conquest two AIs that have no relations with possibly 3rd AI (at least not good relations) and then i have a lot of population ~50%... then you can pump it to 60 % to vote you yourself and plan B is pump relations with one AI (not you rival)...this mostly works but often if you manage to wipe 2 AIs you simply can't stop and end up in domination or conquest;)
good luck!

A proper diplo victory is very satisfying. Some tips:

- Don't be friends with everyone. Find out who is hated and hate them more - join in on wars against them and encourage others to do the same.
- You need long periods of open borders, trading resources and a beneficial trade relationship. Just this usually gets you up to +7 or so.
- Keep an eye on who your rival is. You must be liked more than them. Use bribes to manipulate the relationships between the AIs.
- Increase your own population as much as you can - Sids Sushi is good for this.
- Near the end check out the favorite civic of all the AIs you want votes from and switch to them. Cristo Redentor is good for this and on the mass media path.
- Always keep gold on hand so you can take advantage of random events to improve relations.
- Stay in free religion unless you can rely on votes from a single religious block.
- If the AIs like each other you can form defensive pacts for even more +s. However if the AIs you want to vote for you don't like each other avoid this - you might get drawn into a war you don't want.
- You must try and keep the AIs you want votes from from fighting each other. If they do start a fight see if you can bribe the fight to end before they ask you to join in. Starting a war with a third party and bribing them both to join in will improve their mutual relations.
- Avoid dogpiling your rival if possible. Your rival needs to stay largest but unliked. The worst problem is if your rival gets dogpiled and suddenly your best friend is top in population and the votes of your block are split.
- Use Sids Sushi or other corps to increase the populations of allies and possibly your main rival also (to keep them from falling below the population of your allies).
- Use war to decrease the population of your rivals allies but not your rival themselves.