If you are already leading in tech (or not being behind), you can try bee-lining Archeology and stealing as many of her dig sites as possible, those are the ones generating tons of tourism after Hotels/Airports, especially next to their capital.
after stealing ~2 antiquity sites inside another civ's borders, their leader will tell you that "We have noticed that you have been taking artifacts from our lands ...blah blah.." regardless if you have open borders with them or not. (i don't even know if an Archaeologist can enter foreign borders w/o having OB.)
you can then reply with "We're sorry we won't do that anymore" or "We'll dig where we please"
this happened to me about 40 hours ago when Bismark came up and said that to me. i said sorry i won't dig anymore and he says something like "Good. Those sites are our cultural heritage, not yours." i was rolling in my seat! great job on that, programmers
however, once you do get Archaeology, there are usually TONS of dig sites that pop up over the world; i believe that 50 spawn each game?? usually enough of these sites will be in your own borders or neutral ground.
does anyone know if an artifact you dig up from each civ in a game is worth more Tourism to certain other civs? if it does not matter which civ an artifact is from, then i'll start just digging all the sites nearest me b/c it's obviously the easiest thing to do. up to now, i've been trying to grab dig sites all over the world from all civs, but have noticed that the headline Tourism bonus is always the same.