Part time job in Japan for student?

I'm planning to study Japanese in Japan this year and have been thinking of a part time job. I have money saved and I'm staying with my brother in Tokyo but would like a part time job a couple afternoons/nights a week. I'm part Japanese but I'm a native English speaker and so my Japanese isn't that great as I only use it at home for things you'd say everyday around the house. Nothing technical and I can't converse fluently.

The only jobs that English speakers seem to get are as English teachers or in bars. It's a bit complicated finding a job through the internet so would it be ok if I tried looking for a job when I get to Japan? The semester starts in April and this is the time when English teaching apparently starts too. Would it still be possible to find English teaching jobs whilst in Japan around mid year? Or do I need to start looking for one right now before going? I'll be graduating from University very soon and if I need to I can get a Japanese passport.

I'm also not sure if finding such jobs is easy or not as I've read some people saying it's really easy while others saying it's not easy because of the economic state.

If anyone with experience could help me it'd be appreciated. Thanks

Well I would highly highly suggest you get the Japanese Passport.

If you have one it is proof enough you are a Japanese National and you have no restrictions on work.

If you come on another passport with a student visa, you first need to apply for permission via the school for part-time work only, which is limited to about 20-28 hours a week. If you have a Japanese Passport as a Japanese national you can work anywhere, any time you want. Something regular foreign students cannot do.

As for jobs, I know many students who work in restaurants, convenience stores, etc. just study the language and work hard.

April is start of school season if you plan to teach as an ALT which would be extremely hard if you are going to school during the day time. Language Schools on the other hand hire year around, so you can pop in one and see if they are hiring. It's hard to get one over the internet now since you don't have a Japanese passport or do not have a Visa for in Japan yet (if using another passport).

Thanks for your help!