I graduated from high school. Then I studied networks for two years. After that, I studied English for two years, and now I am looking for a (good) job. I agree with the other correction. You MUST use proper capitalization and punctuation. I have put those changes above. I removed "diploma" because I was a little confused about the combination of the words "networks diploma". Normally I would say I have a degree or certificate in English or computers or whatever.

I graduated from high school and then studied towards a networks diploma for two years. After that I studied towards an English diploma for two years and now I am looking for a job . Comments: (1) You MUST write I with a capital letter. (2) You study towards or for a qualification. (3) Don't say you are looking for a "good" job. Of course you want the job to be good! It goes without saying. You should probably say what area of work you are looking for. (4) You should say "looking for a job" not "lookng for job" and you should say "a networks diploma" not "networks diploma" - you need the indefinite article "a" in both cases. What is a networks diploma by the way? Some sort of computing diploma?