Print-on-demand niche questions

Hello.

Recently, we started developing a website for the client, but unfortunately, it ended up bad, due to a non-payment issue.

Thus, project remained untouched, so we thought that it would be a great idea to have it work for us.
The project consists of a WordPress-based ecommerce, with optimized SEO in theme level (and we will obviously have it done in content level aswell in the future) - but with no specific target group/collections etc.

We have integrated Printful service - which prints shirts on demands and we will have our graphic designer, design some stamps, so this will help us have zero stock and provide orders through printful immediately.

However, since we have no corporate idea and we are not into textile - I started thinking ideas about what would be a cool niche to target on, which stamps, keywords etc, but Im obviously so confused, not knowing from where to start.

Whats your suggestions guys? Should I follow a waterfall method using a keyword analysis tool etc?
Or, any other ideas?

Thanks in advance

I am in the print on demand business too, so here are some tips, based on my experiences:

- Try to find niches that people can strongly identify themselves with (Like sports teams, dog breeds, hobbies etc.)

- If possible: Try to integrate a shirt design tool into your website. People love to take designs, symbols etc. and write their own stuff under it. This is what works best for me. I make many symbols designs, like handsigns and other things and people use the online creator tool, to make their own unique shirt out of it.

Great idea - thanks for it.
There are lots of customizers I can integrate into WooCommerce, but I think that Printful needs be-defined templates to be there.
Are you using Printful?

No I am using POD Platforms like Spreadshirt and Shirtee