Originally Posted by enyafriend (Post 570053)

I can see that you are a Japanese learner and will help you with your sig here.

ニジロと申します。　どうぞよろしく！
While this is not wrong, the standard polite way of introducing yourself would be ニジロと申します。　よろしくお願いします。

ミスをすれば、訂正しなさい。
しなさい is very wrong here. That would make you very rude and authoritative. Instead of asking for "please correct me", you turned out to be demanding that "you correct me!"　
しなさい is very often used a mother to her kids, or you to someone below you in age and level.
もしミスがあったら、どうぞ訂正してくれませんか。is one way I would say it.

私は、とても上手じゃなくて、こっちにIMしてください juffabeast それから、日本語を一生に話しましょう
The proper way to speak in Japanese is either it is in colloquial or polite, but never mix colloquial words with polite words together in a sentence.
While the rest are polite words, こっち is colloquial here and unsuitable for writing use. 　
一生 に is very wrong here. It means forever, in a lifetime, or for life.
一緒 に is the correct word for together.
日本語を一生に話しましょう
>>Let's speak Japanese for life (forever and ever)
日本語を一緒に話しましょう
一緒に日本語を話しましょう
>>Let's speak Japanese together

とても上手じゃなくて >>> そんなに上手ではなくて
とても is very
そんなに....ない is not very

I hope that clears things up a little.

Originally Posted by Debezo (Post 570805)

That's correct, was my suggestion to your sig. (enyafriend beat me.)
Good luck!