I used to work in politics, where sadly, the goal is to change people's opinions. At this level I did succeed in changing many opinions.

The most effective way to change an individual's opinion is to calmly provide facts to them without commentary or judgement. No insults, no judgement, no snark. Just calmly engage with their points and empathise with them. Most opinions are formed without knowing all the facts. Presenting facts without attacking their ego is the best path for changing an opinion.

This works best on unfamiliar topics people don't yet have strong feelings about. With opinion formation, the side to set the first emotional frame has the advantage. This is why in a referendum campaign it's so critical your message reaches voters before the other side can define the ballot question.

Other things I learned

- Good marketers in politics understand psychology. Repeat exposure better encodes a message into memory. For political ads this means repeating the same key phrases/words over and over again, to a degree you and I would find weird, to ensure you encode them into the viewer's memory. With enough repeat exposure, people feel like the ideas are their own.

- Never repeat your opponent's framing of a lie. To debunk a lie: use a "truth" sandwich. State your truth first -- first frame gets the advantage. Next describe the lie in less incendiary words, debunk it, then repeat your frame on the issue repeatedly.

- Politicians start every day with coordinated key talking points for media interviews because message repetition = encoding.

- Referendum ads are particularly crazy because they have no candidate reputation to protect. They do not need to be reasonable or respectable. A referendum ad's sole purpose is to persuade with the most emotionally resonant messages it can to encode key messages/frames of thinking. Being controversial just helps to create more exposure and people seeing your message. If everybody in the media is "debating" the merits of your message frame you are winning. People vote on the issue, not on the campaign team. E.g. If an ad says X will lead to extremist neo-nazi soldiers goose-stepping the streets, people will scoff at the hyperbole while it still subconsciously encodes into them that maybe I don't want something that risks instability.

- Politics is tribal and people follow the support signals sent by elites on their favoured side. Powerful elites speaking out in favour or against something/someone greatly changes its support among coalitions.