Getting insights on categories

I am data guy and analyst who is looking at helping a friend with her ecom business. I plan to invest in it and help grow it. Currently doing less $1m a year and profitable enough to pay herself.

My first takeaway is she is not data driven.

She has products in multiple categories.
There is not scientific approach to pricing.
There is no competitive analysis or looking at a category to see if we should be in it or out of it.
New products are launched on gut (she has a good sense of it) but there are products that fail. She has a good supply chain but no category insights to launch new products. She does great analysis of her sales but has no way to assess if she is a market leader.

Seeking some wisdom how people do this in their business and What are the best tools to get and analyse some of this data?