I am learning Japanese!

[taken from your revised version]
I'm (better with, I am) preparing for my Japanese test. I am teaching learning Japanese myself. I wanna want that Japanese frineds friends to help me to learn Japanese well. If there is someone who is learning Japanese, i I think (that) we can learn it together, and help each other! Meanwhile, I still learn English everyday!


N.B.
1) The apostrophe in " I'm " (as a kind of abbreviation) is usually used in informal writing.  For formal writing, it is necessary to avoid such abbreviations.

2) As you are a learner in Japanese language, it would be better to use the term "to learn" instead of "to teach", in order to describe your learning process.

3) "wanna" is a colloquial term of "want to".  The term, however, does not well fit into your given context, as you need a conjunction "that" to start a subordinate clause (i.e., "... Japanese friends help me ...").

4) "to help sb. do sth." -- The preposition "to" is not used after "help" + inf. 

5) The conjunction "that" after the clause "I think" is optional in conversation, but its presence in writing would let the passage be much clear.

Take care, and good day.

I am learning Japanese!

I'm preparing for my Japanese test. I am teaching Japanese myself. I wanna Japanese frineds to help me to learn Japanese well. If there is someone who is learning Japanese, i think we can learn it together, and help each other! Meanwhile, I still learn English everyday!

I am learning Japanese!

I'm preparing for my Japanese test. I am teaching myself Japanese myself. I wanna Japanesee [friend / teacher] to help me to learn Japanese well. If there is someone who is learning Japanese, i think we can learn it together, and help each other!