I arrived somewhere. (Where?)

Everyone uses English; it's so good for me.

But, still my English my English is still not good.

And sometimes I can't understand what others are telling because I don't know grammar or difficult words.

So, I must try hard. "I must try very hard" or "I must try harder."

Keep trying! Good luck!

I arrived somewhere

Everyone uses English which is its so good for me, but

But, still my English is not good.

And Sometimes I can't understand what others are saying to me telling because I don't know enough grammar or difficult words, so

So, I must try harder.

It will read like this:

I arrived somewhere. I started my study abroad. Everyone uses English which is so good for me, but still my English is not good.

Sometimes I can't understand what others are saying to me because I don't know enough grammar or difficult words, so I must try harder.

Note: Do not start sentences with "but", "and" or "so".

I arrived somewhere

Everyone use English its so good for me.

But, still my English is not good.

And sometimes I can't understandwhat others aretelling because I don't know grammar or difficult words.

So, I must try hard.