I play the game at Marathon Mode and Prince difficulty because I don't want to face a cheating AI at higher difficulties.
I typically win Cultural victories simply because I like social policy benefits and thus invest in all of the cultural buildings for every city.
I'm concerned that I will need to abandon what is best for my empire's strength to gain a victory condition/ hamstring someone else.
I tend to think more in terms of growing my own empire than winning the game.
(Well, I also play world police to keep small empires in the game later on: but thats a secondary objective.)
To maximize you empires Culture in civ V you
1. build cultural buildings (reduced strength in BNW)
2. get cultural CS allies*side benefit=resources
3. build Wonders*side benefit=wonder effects
4. get Landmarks (From Great Artists G+K, from Archaeologists and digs in BNW)
5. get Great Works (from Great Artists BNW)*side effect=Tourism
6. Artist Specialists (which give Great Works BNW)
Effect of Culture in BNW
Policies (as before)
and
Tourism resistance
To win the game maximize Tourism..which means
Maximize Great Works/Artifacts (which produce culture as well)
Build Hotels in cities with World Wonders/Natural Wonders/Terrain culture (and maximize that culture)
So to Win a Cutural Victory, you will be generating a Lot of Culture
[only ways to boost tourism without boosting culture]
Futurism/Personality Cult/Media Culture/Dictatorship of the Proletariat/Cultural Revolution tenets
Hotels
Theming bonus (possibly it might boost culture as well)
Great Musician Concert
Diplomats
Open Borders with other civs
Trade routes with other civs
Shared Religion/Ideology with other civs
And the benefit of Tourism itself (besides winning) =unhappiness of other civs.. enough and their cities join yours.