When asking a busy person for advice, be specific about why you're asking them, request a short meeting like 30 minutes, and come with three concrete topics you need help with. Generic compliments don't work. Respect their time and they're more likely to say yes.
Chapters
If you seem genuine and you actually want their advice and it's someone that's like super relevant, right? They're working in your field or in your space. Obviously don't start with, hey, I know you're an angel investor, but like, hey, I know that you have worked with a lot of companies in this space or you're an expert in this space. I'm just starting out. I would love to pick your brain for 30 minutes if you have time. I think the other part of it is to come with a clear agenda. So these are the 3 things that I need help with that I would love your thoughts on. As opposed to just, hey, I'd love to talk to you for a half hour. I get a few of those and it's really hard to answer them because I don't have a lot of time.