U know, from my point of view the best thing to do is to write about everything little by little, because u see its a good opportunity to get acquainted with foreign country and its usuall life)
the answer is : everything!
Write about anything you want, just like me, I've had no idea what to write about here, when I started my diary.
It's a pleasure to read in English "temps en temps".
I'm in Paris now, and I miss Russian and English (languages and people). You now, those French... They are proud of themselves, not even attempting to switch to another language(
By the way, you can describe people, countries and traditions from your point of view.