How can I distinguish world wonders from national wonders from the tech tree or production list? Do I have to go into the help?
All National Wonders require you to build a certain improvement in every city you control before you can build them. World Wonders do not.
Mouse over the wonder to view its description. If it includes "requires a foo in all cities", it's a National Wonder.
Additionally, the Artists' Musicians' & Writers' Guilds are also considered National Wonders.