Ideas for POD?

Those who are doing POD where you get the print ideas?

Most of it comes on a whim, an event that happens in the news or niches analyzed.

The simplest nevertheless is a niche that fascinates you. If you have a passion and you see yourself wearing a t-shirt in relation to this passion, you will be the first customer and you will know who your typical customer and you can present your offer to this typical customer