When most people think about starting a business, they jump straight to something big, like an app or a restaurant. But the ideas with the most potential are usually right in front of you. Planning events, fixing your friends' resumes, even doing handstands: people really do get paid for every one of those.

The problem is you can't see your own skills. You've done them so long that you forget what it was like not to know how. So you tell yourself "lots of people already do this" or "why would anyone pay me for that?" We call this your Brilliance Blindspot.

Four questions get you past it:

1. What do I already pay for? If you pay for cleaning, meal prep or a trainer, other people do too.
2. What skills do I have? Count the small ones, like being organized or explaining things well.
3. What do the people around me say I'm great at? They see it more clearly than you do. Text five of them, friends, your partner, your family, and use the message below.
4. What do I do on a Saturday morning? What you do when nobody's telling you what to do shows what you actually love.

Hey, I'm doing a 3-day business challenge and one assignment is to ask people I trust a question. If you had to name 3 things I'm good at, what would you say? For example, I always come to you for advice on [investing]. What would you come to me for?

Some answers will be vague, like "you're really thoughtful." Write those down too. They're nuggets, and nuggets are all you need today.

Feel free to come up with ideas that suck. You don't have to know how you'd make money from any of this, or how you'd deliver it. That's what Day 2 and Day 3 are for. Today, start with any idea at all and get it on the list.

Interview me one question at a time about what I'm good at, what friends and coworkers ask me for help with, what I've been paid for before, and what I could talk about for hours. After 10 questions, give me 25 business ideas based on my answers. For each one, name who would pay for it.

Yesterday you wrote ideas down without judging them. Today you judge them.

The fastest way is a back-of-the-napkin tool I call the Demand Matrix. For each idea, ask two questions: how many people would pay for this, and how much would they pay?

• High End: few customers, high price. Think Ferrari. This is where I like to start, because you can test it with a handful of people.
• Golden Goose: lots of customers and a high price. It doesn't come around often, but when it does, it's amazing.
• Mass Market: lots of customers, low price. Think McDonald's. It works, but only at huge volume.
• Labor of Love: few customers, low price. We once spent about $50,000 building a healthcare course. Nobody wanted to pay for it.

There's nothing wrong with a labor of love. If you want to volunteer somewhere, great. Do it. Just don't start your business there.

Don't worry about getting this perfect. There's no data yet, so go with your gut. Some ideas fit in more than one box, and that's fine.

Here's my list of business ideas: [paste your list]. For each one, tell me what people already pay to solve that problem today and roughly how much. Then place each idea on a Demand Matrix (few or many customers, low or high price) and tell me which ones look High End or Golden Goose. Be blunt, and flag anything you're guessing.

Imagine I decide to start Iron It Out with Ramit. I write an ebook, hire a film crew to shoot me ironing cotton and rayon, and launch it on Instagram. Crickets.

Most people quit right there and decide "this business stuff doesn't work." The real problem is they picked an idea without running it through a filter first.

The filter I use is the Pay Certainty Test. It's two questions about the people you'd sell to:

1. Can they pay? Do they actually have the money?
2. Will they pay? Would they spend it on this?

Say I want to teach personal finance to teenagers. Can they pay me? Probably not. They just don't have the money.

Listen to your own voice, too. If you catch yourself saying "well, maybe they could," that's a bad sign.

Run your top ideas through both questions, pick the one that passes, and say it in a sentence. If it doesn't work out later, that's fine. You've still got the rest of your list.

I'm choosing between these business ideas: [paste your top 2 or 3]. Ask me up to 5 questions, one at a time, about whether the people I'd sell to have the money and whether they'd spend it on this. Then tell me which idea to pick and why. Be blunt.