Still Think About How to Expand Vocabulary

I practised speaking with a language partner recently. She was really impressive. She heard me and was understandable most of the time, because she's already got a fairly large vocabulary. I often learn something important from other learners, especially someone learning Japanese because it is sometimes easy to make out what is necessary or not. This time I seem to have finally understood how important a wide vocabulary is. There is sometimes nothing to say just because I haven't got a considerable amount of vocabulary. It's time to face this issue.
By the way, the title of this post is How to Expand Vocabulary, but I've just written about how important vocabulary is. I'm still trying to find out my best way of learning it.

I'd be happy if you'd take some time to read this writing, correct it, or tell me better alternative expressions.