Your opinion is valuable, your advice even more precious. So, save it. Keep it for yourself. Odds are, you need it more than I do. So, please don't give that sh*t away, certainly not without even being asked, lest you be perceived as promiscuous (with your advice). And you know what they call people who are promiscuous with their advice: assholes. If you're one of those people who can't help but give it away, here is my advice, and yes, you asked for it, or you wouldn't be reading this:
1. Shut the f#$k up.
Shutting the f#$k up is the number one most effective cure for advice-promiscuity. Please note: your freedom to voice your opinion is always sacrosanct. So is your freedom to eat McRibs and have sex without a condom. Use your freedoms wisely. Or risk being labeled an asshole.
2. Before giving your advice to others, try giving it to yourself to see how you like it.
So, how'd that go? Like it? If your knee-jerk reaction was to tell yourself to "shut the f#$k up," well, maybe you've got a point there.
3. Abide By The Rubber and Glue Principle.
Your five-year old nephew is correct: Whatever you say does, in fact, come right back to you. Odds are, whatever advice you yearn to bestow upon others is advice you are in need of following, yourself. This is not my opinion, but a universal truth. If you don't believe me, do an Internet search for "psychological projection".
4. Don't ask for advice.
You know you don't want it. So if you find yourself seeking advice, you'd be better off acknowledging your true agenda: opening the door to being all slutty with your unsolicited advice. But don't kid yourself. You're not fooling anyone. Everyone has a tell, and everyone knows yours. Don't make us see it. It's unbecoming. And you know you wanted this advice, or you wouldn't be reading here.
5. Be a better person.
Your need to give advice most likely stems from a desire to improve yourself. Just do that. It would be a far greater gift to the world than any advice you could ever give.
6. Aversion therapy.
Your compulsion to give away your advice can only exist if you believe that others want it. This is a delusion. It arises for any one of a number of reasons, but the reason doesn't matter. What matters is that you shut the f#$k up. The time-honored and most low-tech method of nipping a compulsion in the bud is aversion therapy. Here's how it works in this case: you wear a rubber band on your wrist, and snap it every time you want to offer unsolicited advice. And if you don't have enough discipline to make yourself do so, then recruit your friends to do it for you. Whenever you begin a sentence with "You should," they will be entitled to snap away.
7. Express yourself creatively.
By finding creative ways to express your feelings, you can effectively take the edge off of your compulsion to offer unsolicited advice to others. That's why I write. It totally eliminates my impulse to offer unsolicited advice. Now you know. But you don't have to write. You can paint or sing in the shower or make grumpy cat memes. The possibilities are endless really. Just find something that engages you, and you may forget all about the fact that you have super-important opinions to share and advice to bestow on others.
8. See a shrink.
With a shrink, you can whine about how everyone needs your advice but is too stupid/closed-minded/afraid to take your advice. Unlike your stupid/closed-minded/scared friends, your shrink won't react by screening your calls. She'll even talk about what it means and why you see things the way you do. Pretend-friend and psychological analysis in one? I call that a win-win.
9. Don't pretend that offering your opinion isn't just another way of giving advice.
"I'm entitled to my opinion," you say. But everyone knows that an opinion is nothing more than passive aggressive advice. No one is fooled. When you say "I liked your hair better long," I know that you mean "Please grow your hair long again." Everyone knows. So just stop.
9a. Corollary to 9: Don't ask a "question" for the sole purpose of offering your opinion.
Example: "Are you going to wear that?"
I know, and you know, and you know that I know, that the rest of the conversation will go according to a script that was written at the dawn of time. It will end with your offering unsolicited advice about what I am wearing. Don't go there. And if you really don't know that, then when in doubt, see number (1) above.
10. Filter the incoming..
Others will offer their own opinions and advice all day long. If you accord equal value to all of it, you will quickly become confused and irritable, and the only way you will know how to make the chaos stop is by purging the unsolicited opinions and advice by giving it all away to others, unsolicited. Do not fall into this trap. Filter what comes in. Then you won't have the need to vomit it back up.
11. Believe in yourself.
Your beliefs do not depend upon validation from others. At the risk of sounding all "woo", I suggest that if you do what you know is right, and if you believe in your own intuition and your ability to make rational judgements and take reasonable actions, you will have no need to get in anyone else's face about anything.
If you can't, then just shut the f#$k up. Please. And always say "please". Thank you.