Self-Introduction

My name is Keisuke, And and I'm Japanese.
I live in Tokyo.
My occupation is programmer.  (Better: I work as a programmer/ I am a programmer)
My hobby is hobbies are reading comics and (singing/doing) Karaoke.
I try am trying to learn English because I want to be friends with people from lots of different countries.
I am not good at English, So so I want to practice in on italki.

Self-Introduction

My name is Keisuke, And and I'm Japanese.*
I live in Tokyo.
My occupation** is programmer.
My hobby is reading comics and doing*** Karaoke.
I am trying to learn English because I want to be make friends with people from a lots**** of different countries.
I am not very***** good at English, Sso I want to practice in italki.

* You can also say, "and I'm from Japan."

** It is more natural to say, "I work as a programmer."

*** "Karaoke" isn't a verb. And because you don't "read" Karaoke (well, actually, I guess you do . . . but the main thing about Karaoke is singing, right?) you need a verb. I suppose you could say "going to Karaoke bars" or "singing Karaoke." But "doing Karaoke" is a good translation for カラオケする。 

**** "lots of different countries" is okay. But I think "a lot of different countries" is more grammatically correct.

***** We often use "very" as a qualifier. It doesn't change the meaning, but it softens the word that comes after it. We use it with negative adjectives with a meaning similar to ちょっと. (Examples: "I'm not very hungry" and "she was not very nice.") We also use it with positive adjectives (to mean とても) as in "the book was very interesting" or "the dog was very cute."