Diplomatic Victory is now the only victory I haven't won.
I have been playing on Anything from Prince...
Prince, Monarch, Emporor... but I cannot win on a diplomatic victory.

I play on a Duel Map with 6 people. (I like lots of people but my laptop can't handle 2000AD when its on a larger map).

I always get the two largest civilizations Friendly with me but they still never vote for me. They either absstain or vote for each other.
Why is this? How can I win?
Another thing, is that whenever I found a religion, another Civ founds one and spread it quicker then I can. Then all of the other nations have 1 or 2 religions across all of them and I'm on my own with my own single religion. I try and build roads to the holy city but it never spreads to my civ so I can't convert and no one asks me to convert to their religion.

Can someone explain how I should be winning.
I also played a game yesterday. Built the apostilix palace and became the leader. I didn't get to make ONE resolution. It just kept asking who should be the leader. No one else was in my religion.

A long time ago I had ONLY diplomatic victory as the condition. Not Time.
So I was always like 4 votes away from voting myself winner by UN victory. So I spammed like 10 cities anywhere and spread sids sushi corp there and within 18 turns I had like 60% of the entire worlds population and had enough votes to decalre myself winner. When it was time to front a resolution, the 'win by diplomatic condition' wasn't there any more. It seems like if you have a majority of the poplulation you CANNOT vote for youself? Losing my 60% of the votes meant I had no way to win and had to just quit the game

To spread your religion, build missionaries and send them to all civs you have open borders with. You'll either need Monastries or the Organised Religion civic to build them.

With the diplomatic voting, you can't vote yourself in with just your own votes, so the option goes once thats a possibility. Best method to get around that is to make an ally who hates the other civ who can be voted for... then they should vote for you.

If they're friendly and still not voting for you, it implies that they're also friendly with the other civ in the vote.

Yeah, one of the other two civs 2nd and 3rd largest formed permanent alliance....
That made me go awwwwww fux!

It's easier to abuse the AP than the UN. The UN you have to carefully plan out who is building the thing along with who will vote for you.

If you have people at friendly it may even be a worthwhile gamble to gift someone who isn't there just so they build it first (assuming you're #1 in pop, and your friends are in the 2-3 range).

Controlling the AP religion is more complicated strategically but much easier once you have the hang of it, hence my signature. I plan on finishing game III shortly.