This reminds me of Brian Balfour's "Four Fits" model which is the bedrock for how I think about companies.

You need four things: (1) a market, i.e. a set of customers with a valuable problem; (2) a product that actually solves that problem well; (3) a channel through which you can reach these customers; and (4) a business model to sustain the above efforts.

A good business idea attempts to account for all of these, and usually starts by looking at the customers and their problems and working backwards. But most new founders confuse "business idea" with "product idea." They focus entirely on the product, which is only one part of a business. And then after they've finished building, they go out in search of customers with problems, trying to fit their square peg in to round holes. I strongly recommend against that path.

#2 is so much harder than people think.

All of the points are really really hard.

Actually everyone has a different skillset, therefore the hardest from the 4 options is different for everyone.

#2 is v hard, I can confirm that. Infact it should be the first thing to be solved

You may have listed in no particular order, but, if you did, I would argue #2 as the most important.

I disagree, and this is the mistake I made earlier in my career. Having the market is most important. I have built great products that flopped and ok products that were incredibly successful.

Quoting Andy Rachleff: If your startup addresses a market that really wants your product, you can screw almost everything up and still likely be successful. On the flip side, if you are really good at execution, but the “dogs aren’t eating the dog food”, you have no chance at winning.

“When a great team meets a lousy market, market wins. When a lousy team meets a great market, market wins. When a great team meets a great market, something special happens.”

It sounds more like we agree. "Having a market" and "The ability to reach people who have the problem my software solves" aren't so different.

But while "people who have a problem" equals a market, it's nothing if you cannot reach them.

The three of them form a triangle. Which side of the triangle is most important?

This is not a magical thing. Id argue it is fairly mechanical. The biggest issue you'd face is fear. Focus first on conquering that.

I think they're all necessary.

Product + grinding - building it and nobody comes, will get there eventually. Easier to learn to sell than to make a good product.

Sales + grinding - selling a turd, hopefully will get there. Harder to learn how to make a good product than sell.

Product + sales - flame out early

How did you tackle problem (2) here? trade shows or something? How do you go from 0 (no connections to industry X, or people who face problem Y) to being able to do 2 without some inside connection?

Re problem 2 - I’ve had decent success using Gabe Weinberg’s Bullseye framework.

re no connections to industry x - if you don’t have connections it means you probably don’t have the insight necessary to solve a problem for people in that industry. I’d probably look closer to home. If you really want to, reach out to people on LinkedIn and offer to pay the first couple for an hour of their time. Then reach out to more people and share insights from the first few. In short, add value. Soon you’ll be an expert.

Read The Startup Owner's Manual, or the previous version of the same, Four Steps to the Epiphany, and apply what you've read.

Add Lean Customer Development by Cindy Alvarez

Loved Cindy's book. Hey talk 'From 0 to Interviewing Customers Well in 90 Minutes' [0] available on YouTube is a great resource too.

[0] https://www.youtube.com/watch?v=d5hc7sseHbE

How are you even going to know what problems need to be solved if you have no connections to industry X?

Very well put - thank you, it's a help for me to focus on