Advising startups is an industry. People seem to go into it when they don’t have a startup going on, or they don’t have the energy to get back into startups. Occasionally, they do it because they want to keep tabs on a startup, either to invest or to join. These are all decent reasons.
However, you shouldn’t call yourself a startup advisor unless you have had a successful startup. You can call yourself an entrepreneur, but only if you’ve founded a company of some kind. You can’t call yourself an entrepreneur if you just want to found a company. That’s just called an “employee”.
If I were to advise startups, most of my advice would be “I don’t know” with an occasional “go ahead and try and let me know how it goes”. That way I could take credit for the things that work and disavow all the failures.
I don’t currently advise other startups because I have nothing of much value to tell them. If they are smart, they might figure it out. If they aren’t smart, they might get lucky. In either case, my advice will not be predictive of their success.
A startup advisor is really more of a therapist then a mentor. This often requires age and wisdom.
Successful startup advisors don’t keep honest track records. Highlight your wins, delete your losses. This is the same technique that investors use.
Of course, the best startup advice is this - don’t listen to startup advice.