Ask people what you can do for them. You have to figure this out - what are their actual preferences for where they are putting their money into? How much money do they have to spend?
So you have to adjust in relation to the customer — you have to ask “What things do you usually pay for? Do you ever buy similar products? Do you know what a paid newsletter is all about?
So you have to listen. If someone tells you they are really interested in the stock market, that tells you they have the spirit of an investor. To an experienced sales pro this could be a sign that they would love to invest in something that is financially valuable - so one could adjust and start researching and delivering stuff on financial abundance. To make one’s newsletter an even better investment than stock market? That takes some savvy.
If they say they love art and culture, you could adjust to that and take that to heart - write about beautiful art, music, shows and cultural phenomena. Share your knowledge in that area.
It takes listening and asking great questions.