I listen. I read. I draw from experience. I’m not a certified anything either.
You can give advice, but always stress that it’s an opinion – nothing more. People can choose whether or not to take your advice – that’s their decision. You take the risk of being wrong or having it not work out for them and they might blame you. It’s the risk of giving advice. So be careful.
And if you don’t know the answer, don’t ever pretend to know it. Be honest above all. 🙂