Japan Meets Andrew Marston

Here’s the method I used for getting a job in Japan that was quite successful. After three interviews I had offers for four positions. Please realize, also, that most jobs acquired by foreigners in Japan are English teaching positions.
Side note: Having a bachelors degree is almost a must in order for the Japanese Immigration Office to grant you a visa.

Hopefully these steps help you also.
1 Motivation
2 Come to Japan
3 Apply Everywhere
4 Presentation
5 Flexibility

Not mentioned in the video but added by RisuMiso in the comments is perseverance. Most people will probably get rejected many times before finding a job. This is normal. You may also get interviews, second interviews, and still have it fall through. Keep on trying, and you will find a job.

Some useful job posting sites:
http://www.gaijinpot.com/
http://jobs.japantimes.jp/
http://www.westgate.co.jp/application/
http://www.aeonet.com/
http://www.aeonet.com/aeon_index.php/
http://www.amityteachers.com/

If you want to check out the resume and cover letter I used to get my job, download them here:
Cover Letter
Resume

Some Motivational Material to get in gear:

(this is what coming to Japan has been like for me so far)