Agreed, giving unsolicited advice isn't going to go well. I'm thinking of a time where the topic is pre-chosen like a training or sometime when the audience knows what's going to be discussed, when there's a clear expectation that there will be a discussion. Thoughts on that?
ETA: @Malkynn & @TheGrimSqueaker you both write well and have a great voice in your writing. I'd put you both in the category of good communicators so thank you for responding earlier.
You're conflating unsolicited advice with unsolicited subjects. Just because someone goes into a situation knowing what will be discussed doesn't mean they care even the slightest about your personal input, unless you're the one teaching a course.
It doesn't matter what the context is or how the topic comes up, I wouldn't give anyone advice unless they've expressly sought it and/or already respect me as an authority on the matter.
Knowledge and expertise are pretty self evident in normal day to day conversation, so you really don't have to go out of your way to demonstrate it. If people recognize that you have knowledge, they will likely seek it out from you, and actively give you the authority you require in order to offer advice effectively. If they aren't asking, you aren't managing to demonstrate knowledge.
The best method BY FAR for establishing your knowledge is in the questions you ask, not the statements you make. So it all comes back to putting your energy into understanding the people involved.
If your goal is to establish your own intelligence in a conversation, assume that anyone you are talking to is smarter than you in some very important way and has something to teach you.
Extremely intelligent people are intelligent because they constantly seek information, not because they constantly seek to impart their own on others. They already know what they know, so it's not actually that interesting to them, and they will impose it only when asked or when it will enrich the conversation and their own subsequent learning.
The moment I encounter someone with behaviours that differ from what I think would be best, I try to understand what motivates them, I don't just assume that I know better than they do how they should behave in their own life.
Because at the end of the day, that's what advice is, it's a declaration that based on your own very limited personal experience, that you firmly believe that you know better how others should live their own lives.
You had better be damn sure that you're right before making that claim.