If you're trying to convince the other person, be humble. Be gentle. Be subtle. Ask them questions. Let them think they came up with the idea entirely on their own. If any bystanders are watching this discussion, they are more likely to think that the other person is right, or that they are "winning". But this will give you the best possible chance of convincing the person you're talking to.
If you're trying to convince bystanders, project confidence. Present compelling evidence. Pick apart the other person's arguments and show why its flawed. Chances are, this will make the other person dig in even more strongly and resent you. But this will give you the best chance of convincing neutral bystanders.
Use the right tool for each job. If you're using "debate tactics" in a 1:1 discussion, you will never get the desired results, no matter how data-driven and logical your arguments are. I've made this mistake far too many times, and this seems to be what OP is getting at as well