Let me give you some advice: give advice.
Not all the time, but some of the time.
Yes, it does imply that the person you're talking to is not "an adult capable of making their own decisions and taking responsibility for their own life".
And often we're not.
We have a ton on our minds. We have the capability to figure out our own problems, but we have more problems (areas where our lives are not optimized) than we have time to figure out and optimize. And that's even LW/tech/intellectuals whose first thought is to google it. Most of humanity for most of history has tended to just guess and try stuff unless they've happened across someone who's said "I actually know something about this." My most frequent advice is "have you googled it" but even there I find people who've found some dumb SEO optimized page with terrible advice - and they haven't known or bothered to look farther.
Why is someone telling you their problems if they don't want help figuring them out? Usually they want some mix of sympathy and help - and they don't know which because they don't know how much you can help them. Figuring out which is appropriate is a very useful skill.
This is not to disagree with your suggestions; asking questions before giving advice is a great idea; it really helps establish whether this is an occasion where your advice might be useful.
I will quibble with your second one; sharing from personal experience rather than from your knowledge of other people's experiences seems limiting. If your personal experience in the topic is looking at academic papers or Reddit accounts of success and failure stories, that's highly worth sharing so that this person doesn't have to re-do all of that work and spend all the time you did to get up to speed.
When people offer me advice, I feel cared for, and it often helps me think through the issue from a new perspective. I do wonder if they think I'm not an adult who's taking responsibility for my own life - and often I conclude that they're right, I haven't yet taken responsibility for that particular aspect of my life.
And yes, it is helpful to couch your advice in the form of a question, to avoid implying too hard that this person is lazy or an idiot[1]
We are all lazy and an idiot some times and in some areas. We have sharp cognitive and energetic limitations. We're doing great for monkeys, but recognizing that we're all deeply limited and imperfect is not only realistic, it's freeing.
I like the three suggested approaches instead of giving advice directly. All three seem like good ideas.
However, all three of your approaches seem like things that could still be done in combination with giving advice. "Before giving advice, try to fully understand the situation by asking questions" seems like a reasonable way to implement your first suggestion, for instance. Personal experiences can be used to give context for why you are giving the advice you are giving, and clearing up misconceptions can be an important first step before giving more concrete advice. This doesn't mean that these approaches need to be combined with giving advice, but they aren't in opposition to it and can perhaps be the thing that shifts us from bad advice to good advice.
In general I see you trying to tip us into a more collaborative frame with friends or collegues who come to us with problems. Instead of immediately trying to solve their problem independently, try to work with them to better understand the issue and see if you have something worthwhile to add. This makes sense to me.
I find your second paragraph oversimplified. It's not at all clear that being in different circumstances means your advice doesn't apply to others. There are many situations where it's exactly because you come from a different perspective that you can expect to have useful advice.
My final criticism is with respect to the idea that advice is no longer applicable in the modern world of the internet. I don't think this is true. A lot of the time people simply don't know what options are available and so wouldn't even consider looking for entire classes of solutions without being given advice that guides them to it. There have been many cases in my own life when I've benefited from advice when I didn't even realise I had a problem: I was doing something in a way that worked but was highly suboptimal, and when a friend saw what I was doing suggested a simpler and more elegant solution that immediately made things easier for me. I wouldn't even have thought to ask (or to search the internet) for a solution to this problem, because I already had a solution, and so didn't think of it in terms of having a problem to be solved. In these cases unsolicited advice was highly useful for me.
I think there's a good reading of what you are saying as "advice is overrated", and you are trying to shift us to a more collaberative framework. Since advice is overrated and reactive advice is overused, maybe a heuristic like "don't give advice" is useful to shift us away from a typical immediate reaction to friends with problems where we typically try to solve the problem immediately rather than simply asking questions to delve deeper.
I am often tempted to give advice, and find it difficult to say nothing while friends and colleagues make decisions that seem (to me) obviously wrong.
But advice is by nature bad, and it is not hard to see why. We are different people living under different circumstances. Giving advice is not only unhelpful, it is often harmful. You may give a friend bad advice and have them come back to blame you (“I thought stocks only go up!”), you may come off out-of-touch or privileged (“oh sure I’ll just strap on my job helmet”), or just alienate your friend by sounding patronizing.
Yet the temptation remains. A friend comes to you with a problem. You feel you should say something other than just lamely offer sympathy. But what?
Here are a few options:
Are there exceptions? Should you sometimes just tell people what to do? Maybe in a pre-internet era when it would have been tough to find tips on improving sleep hygiene or whatever, but with most obvious context-independent advice just a click away, there aren’t many cases like this. Maybe intervening for an alcoholic, but even then only as a group.
This somewhat proves the rule that the only time to give advice is when a friend is, in some sense, not an adult capable of making their own decisions and taking responsibility for their own life.