Ask HN: How Do I Improve My Native Language Skills?

This is going to sound really weird but I think I am horrible at English. I feel like when I speak I sound like a drunk even though I never drink because I don't feel fluent in my native tongue. Any ideas on how to fix this? I know this is not related to startups,programming, or any of those things. I do however feel being able to communicate properly in English is vital part of all of those things.