Check online journal advertisements. I found my first postdoc in Nature, though I never wrote a paper for it yet.
Check web pages of university or institute job opening. It is easiest way for them to find candidates. Very often they already have some candidates in their mind, and job interviews can be just a fake process they must go through.
Job opening information through people you know is the most reliable source of information, and very often you do not even have to go through an interview process before you get accepted.
Scholarship: if you do not like to be bounded to a given country, do not get a scholarship. Many Japanese scholarship expect you to come back to Japan. Also you probably have to write application in Japanese. And often they require you not to have lived in a foreign country more than a certain period. So if you studied in another country and do not feel like to write Japanese applications, you can just focus on getting an opening just like any other people.
Surprisingly you will be accepted as long as you have sufficient qualification, but it is very important to understand the task you are expected to do.
There are many good groups but getting into these groups is tough. And also there are many groups you do not want to get involved.