How to decide newsletter format and audience?

Hey everyone!

Long time lurker, first time poster. I'm just starting out on the journey and it's a scary first post.

My end goal is to have a profitable business that gives me flexibility and lets me help others further their education.

However, before that, I want to start with a newsletter that would help me build an audience.

I'm having trouble determining the segment of my audience to target.

Deciding that, will help me decide on the format:

• List of links / curation (like DataElixir)
• Spend 5 Minutes and learn one thing (what I currently have on the landing page)

A few questions:

1. What do you all think of the idea and the planned approach?
2. How would you recommend I decide how to nail down the format and audience
3. What's a good way to promote - I plan to tweet to my audience, but I would LOVE other suggestions.
4. I would love some feedback on the landing page