Join every forum that revolves around problems or issues people have and see how people in that area are using the niche you want to build a website around :
For example: I would like to do a website on how technology is helping mental health and physical wellness.
I'd most likely join as much forums as I can, go to their members section and find how tech has help with particular problems EX:
Hi and I'm new, My name is Brad
I'm wondering if there are any electric consoles or wearable technology that can help me get better control of my sleep. Does anyone here have any personal experience with them?
As I can imagine this can also make for creating rich and original blog post material and possibly YouTube content.
Again. I don't know shit about affiliate marketing or online entrepreneurship. I just started diving into all this shit about a week ago.... just my thoughts. Let me know what you think.