I can't believe no one has mentioned writing - try thinking about something you strongly believe in (but others disagree with, like a political/philosophical vi

I can't believe no one has mentioned writing - try thinking about something you strongly believe in (but others disagree with, like a political/philosophical view), then write out your argument for why it is true. Then write out what you think your opponent believes and think about how they would pick apart your argument. Then rewrite your side again. Have someone else read both sides and critique each. Also try explaining how to do some task. Give it to someone else and, based only on your instructions, have them try and do the thing you laid out. We're they able to do it effectively? What questions did they have and where did they get confused? These will help you improve your explanation and argument skills.