Just a few tips here to make sure you're not making and mistakes in your interviews:

1) If you have a pre-defined idea for what you want to make going into the interview, don't mention it until the very end of the conversation.

Get through all your questions first.

Asking a customer "Hey I have this idea, would you buy this?" is never an accurate data point on a customer. People will often say yes just to support you, but when it's time to actually spend the money there are a ton of reasons they might not find value there.

But, you can ask their opinion at the end, just don't take what they say too seriously. It can end up providing some nice feedback though.

2) Your interviews (ideally) should be about an hour long.

A lot of mine have gone longer, so you just want to make sure you block of the time you'll need.

3) If you have an idea, don't get attached.

I'm sure your startup idea is great, and if you're doing customer discovery to validate your idea, that's awesome. But everyone I know has had their idea morphed through customer discovery. No matter how smart you are, if you don't know the industry back and forth and have the exact same perspective as the customer you're interviewing, you're not going to be able to predict exactly what they want.

Just don't be stubborn, and if you hear a problem that's different from your own when you're doing your interviews, consider it.

Whenever I've insisted I'm right, my idea goes nowhere, and not a single customer is interested.

4) Do NOT assume their solution is gospel

You're the one building the product, not them. Plenty of people you interview are going to believe they know how to build the product better than anyone, and while you should take their input into account, you have to remember their expertise isn't in building these types of products.