Best way of monetizing a website with visitors from all over the place?

I’ve got a website with visitors from the US (40%), Japan (10%), Uk (5%) and the rest split between the rest of the world.
I’ve put Google adwords on and some money is trickling in. I’ve also tried Amazon but this only targets the 40% that visit from America, unless I sign up individually with their other affiliate schemes in other countries, and I’ve had no conversions yet anyway.
Does anyone know if there is another alternative for this situation?
Thanks!
ps - It’s a Japanese language learning website

I would have to see the site, but I would say that learning Japanese, you would have to think of more than just americans wanting to learn it. My daughter is learning it and she’s in college, she got rosseta stone for Chinese a few years ago

What do you think about working with Google AdSense (premium traffic), Fidelity Media and AdBrite (remnant traffic) + affilate program for increasing your revenue?

AdSense probably has the greatest number of advertisers from across the globe, so definitely worth keeping them in the mix.
If you’ve got the traffic - sign up for some traditional ad networks too like Tribal Fusion, Casale Media, ValueClick, and Burst Media.

If you run your ads through OpenX or Google Ad Manager, then you can have your US and UK traffic going to US/UK ad networks, your Japanese traffic going to a Japanese ad network (I’m sure there are plenty but I don’t know Japanese to find out!), and then default the rest to AdSense. Or you can geotarget affiliate programs in the same way.

This is only really worth the effort if you have decent traffic though…

I’ve been using google translator on both my droid and web and it’s been a great help, just sent out a email in English, Russian and Danish

Thanks for those tips. Last month I had approx 42,000 visits and 136,000 page impressions - this is more than I expected when I made the site but not sure if it would qualify as ‘decent traffic’ ?

That is definitely enough traffic to warrant putting in the effort to set up geotargeting and finding relevant networks and affiliate programs in my book!

You never know on these boards whether a site is getting 1000 visitors per month or a million… but anything over 50,000 makes it worthwhile really.

Well, 42K unique monthly visits is not bad and you can definitely try joining a CPM network. Most Publishers Networks accept 300x250, 728x90 and 160x600 ad units, so you should have these placements on your site.
Join several networks who accepts you and see which network brings you the best revenue.

The future of China on the Internet will also have a good development

You can run website individual countries by the help of PPC network . Yes, china good market place.