Entrepreneur

There is a great book about this called "Right It" by Alberto Savoia. One of the main points is that you need to get your own data and other people's data have very limited value. So, approaches like market research, hiring agencies, analysing competitors all sound like nice shortcuts to get the job done quickly but have a big risk of being misleading.

The "Right It" way is to define a hypothesis and go out and test it the easiest and cheapest way you can do. It sounds like more work but will give you additional insights from your target customers that will be most valuable to the idea you want to test and you can't find this information anywhere else because nobody else is trying exactly what you want to try.

From what I've learned, what people mean by testing the market is to create a landing page / prototype to address the business pain point of their target profile or audience.

You'd need some capital for this and a threshold to determine if what you're building is worth continuing or not e.g. Using $X amount of dollars, we expect 20 sales/leads from our ad campaign. Or use other low-cost methods like cold calling / email marketing. What matters is that some kind of threshold between success / failure or 'pivot' is established.

But in the midst of doing this you'd need to develop your marketing skill-ability or hire an agency. But I advise to develop your own sales competency as this will forever be the most vital cog in any business.

For good marketing research, I had to read and watch the best sales and copywriting books / videos to pick templates (they are many of them) that now work in my favour. And I'll tell you this, great marketing research is time consuming and boring, but the rewards are always worth it.