Work your way backwards. Start from the things you’re selling → branch out with relevant topics → create helpful and valuable content on these topics.
How are you planning to write the thing you’re selling in a strategic way?
How often do you plan to email?
If you're just starting out, start with 1 or 2 first.
What type of email sequences/series do you want to create?
If you’re just starting out, start with 1 or 2 first (Impress A Stranger and Flash Sale series).