Search online and offline classified ads. Language teachers and tutors often run ads looking for new clients to teach.
Contact an online language school, such as Berlitz, Rosetta Stone or Live Mocha. Some of these programs are computer-based. Although they might be expensive, both have proven success teaching people Japanese and other languages.
Call a local college or university that has a Japanese department. Inquire if any instructors or advanced students teach Japanese lessons to individuals.
Search the websites of Japanese teacher associations. Some of these sites have listings of tutors in different countries. Not every Japanese teacher listed as a tutor is willing to work with students online; some prefer to work in person.