Hi Karura!
You can always try to apply in Gaijinpot or any other websites first. Some companies post job opportunities there open to foreign nationals like you and they're even willing to sponsor your visa. I went through the same phase as you did and I just kept on applying online. I'm pretty sure you've been trying.
Should you find a job here in Tokyo, you can consider staying at a share house to also enhance your experience here. It's good to have new friends and live in a family atmosphere you know. Share houses information can be read
here (just click it to check out) blog too.
Blessings to your job hunt!