How to live in japan through a student visa?

I'm planning to to study Japanese in Tokyo. I have finished N5 and already started with my N4 studies here in the Philippines, but my problem is I already forgot a lot of what I've learned. My plan is to study again in Japan, and apply for a part time job and before my student visa is finish I plan to apply for a full time work then apply for a working visa. My parents will be sponsoring my education and stay in Japan, but I do not want to depend on my parents to much. How long does it normally take for foreigners to get a part time work? and will a part time job be enough to be self sufficient? Also I will have 2 of my friends with me, they are already processing their working visa and working as an english teacher.

Having a part time job requires often Japanese skill, unless you do not mind working at an assembling line.
Also you need to discuss with the school you want to enroll, since some do not allow you to work, since you come for the study.

If you have studied enough and you can compete with others on the labour market you can try finding a full time job, who is can sponsor you. You cannot get a working visa without having a company to support you.