Im a stoic... But I need help being more "stoic".

I often find myself in debates, conversations, or meetings where I spend a lot of time talking. Sometimes I feel embarrassed about this and that I should listen more. I would rather be the kind of person who speaks only when it's necessary but instead I get excited and am prone to rambling and giving opinions I may or may not be fully equipped to offer. Sometimes I feel as though I can't help myself and don't even realize I've talked so much until long after the conversation.

Any tips or suggestions on how to talk less and listen more? How to maintain control of my habits in these situations?