I'd just like to add that the key to a Culture Victory is Theming Bonuses and Multipliers.
Buildings which have slots for more than one work of art/writing/music/artefact all have a 'Theming Bonus'. In the 'Your Culture' tab of the Culture Panel, when you have built one of these buildings you will see a +0 to the right of the slots. Hover over the +0 with your mouse and you will get a pop up which tells you what conditions you need to meet to score a Theming Bonus for that building.
For example, if you build a Museum you need to fill the two slots with either Art or Artefacts but both have to be the same (either two pieces of Art or two Artefacts but not one of each). The two pieces should also be from the same Era (Ancient, Classical etc) and both should be from either your Civ or any Civs other than your own.
If you meet all the criteria you score the Theming Bonus and will get an extra point of Tourism for each slot that the building has (so a Museum will give +2 Tourism as a Theming Bonus). Some Wonders have 4 slots so you can score a +4 Theming Bonus on these. Each building will have different conditions to meet its Theming Bonus and some are easier to achieve than others.
It's because of the Theming Bonus mechanism that the ability to Swap Great Works is available (it's a bit like trading cards!).
Multipliers to your Tourism output are also very important and they come from a variety of different areas of the game. For example, you will get multipliers to your Tourism against a specific Civ when you meet the following Criteria:
- You have Open Borders (+25%)
- You share a Religion (+25%)
- You have a trade route with that Civ (+25%)
- You share an Ideology (+25%)
- You have differing Ideologies but you have a Diplomat spreading propaganda (varies?)
There are others and there are also penalties as well. Furthermore, the AI gets the same bonuses against you so if they have a trade route with you but you don't have one with them for example, they have an edge with their Tourism influence.
There are a lot of Policies, Beliefs, Tenets, Buildings and Wonders that can boost or multiply Tourism too (and later in the game there are mechanics which will convert some of your Culture into Tourism as well). France, Brazil and India are three Civs who have Unique Abilities or Buildings which directly contribute to Tourism too.
Hope this helps!