Giving free counsel is worth little. Unasked advice even less.
To intervene spontaneously in somebody else's problem is generous but risky intruding, seldom appreciated.
Counsel is friendly critique, but those who need it most like it the least. They tend to confuse it with censuring. To give or to face criticism requires courage .
Weak people - and most people are weak - misunderstand the gift of spontaneous counsel; the common place is that the one taking risk to intervene in somebody else's business is a mingling fool and a fool – even a wise one - is not credible. Folks even consider that you have a need to talk and they do you favour* with their time to listen.
For most people, the worth of advice comes from a height and distance of authority, wealth, power, celebrity or success rather than from insight and sympathy. Flatly, for the stupid, that which costs nothing is worth nothing.
Therefore, if you want common people to respect your advice, let them feel the heat first and make them pay for advice with formal respect, some sacrifice or why not, with money. Let them make an effort to obtain it. "On demand". The chance is better to have your judgement followed. Cause people to ask for it as they ask for salt at table; postpone, wait for the felt need.
To be asked, make your competence visible but do not push it. Great things are visible from far, like mountains, but they do not move. Let people come to them. I know, this requires patience rather than enthusiasm to help.
The signal that people are open to advice is simple: they ask for it or show despair.
All this cheap practical wisdom, which I resent as sadism, is the human comedy of advice-giving.
I know its truth but alas, I do not have the heart to be wise in this way. I used to be a consultant. Giving counsel to other people was one of my strengths , beyond some expertise, because I was bold enough to tell the truth to harsh individuals everybody feared and lied. I helped lost people because I allowed myself to intrude, for compassion and sense of justice, when they were in need of someone to tell them what to do. I was paid for this, but I preferred doing it for free. At best, I would be rewarded with respect by the tough and gratitude by the needy. Occasionally, the stupid misunderstood me and the mean took advantage of me.
Keep in balance being generous with being professional.
* As one who earned his bread, quite comfortably, as a consultant well paid and occasionally acknowledged for advice in difficult situations, I keep being surprised when I encounter this attitude; I believe I am generous, while the listener believes that I am boring. They may be right.
 I must also confess that, like Alice in Wonderland, I often gave very good guidance to myself though seldom followed it. This awareness helped me evaluate the force of our weakness: “She generally gave herself very good advice, (though she very seldom followed it)” Lewis Carroll , Alice in Wonderland, Chapter I.
 This is how I learned to look into one’s eyes and say with a casual air: “This reminds me of a story...” Stories are examples that carry advice, as if about and for somebody else.