Cold contact people.
While I've never been part of a proper startup where you'd want advisors, I have reached out to folks in general including those that have successfully sold startups for large sums of money.
You'll get rejected. A lot. The vast majority just won't reply to you. Do NOT take this personally.
Some will reply and give you an excuse (real or fake), 'hey, I'm busy with this or trying to raise funding for something or my dog currently has diabetes and we're trying to dial in his diet can I get back to you in X amount of time' and chances are you can go ahead and write them off because in my experience most aren't interested and just aren't the kind of person to flat out tell you no. Again, don't take it personally.
Eventually, unless you botch the contact emails, someone is going to reply. Be cool. Read the email. Read it again. Read it again. Yeah, you read it right. They replied favorably. BE. COOL. Digest what they said, think out your reply, type it out and leave it as a draft. Come back to it a half hour later and read it again, still sound good? Send it.
Keep your initial emails brief. "Hi Mr. Smith, I'm Ryan. I noticed that we had these similar experiences/both had a passion in the same industry or field/etc. I'm doing thing and I feel lost about other-thing. I'd really appreciate if you have any time to point me in the right direction, I can make myself available at any time to have a quick call or can send you more info via email. I know you're very busy but I'd appreciate any time you can spare."
You don't have to go after a billionaire or even a multi millionaire. You can just find someone working in the industry you are trying to do something in and reach out, you'll probably get better response rates this way and will likely find just as valuable (if not more so, a lot of successful start-up founders will claim luck was most of their success). If you go for 'lower-rung' people you can target people in your city and, ideally, offer to buy them coffee or dinner if they'd talk to you in person for an hour. You can get actionable information MUCH QUICKER in person.
>Any suggestions from the HN crowd to avoid wasting my time trying for find someone?
If you spend 100 hours writing emails, LinkedIn messages and phone calls as long as one person agrees to a chat, you've not wasted time.
Just remember, these people are probably far more busy than you are. Be patient, be respectful, accept rejection and move on.