Narrowing My Niche-part 2

I have listened to all the Entrepreneur videos. I have a blog that is established and have 450 subscribers. I am unsure if those subscribers are part of niche, career focused women attorneys working more than 50 hours a week. I am wanting to find a platform where my niche is. I have asked a lot of my women friends, that I went to law school with and work with their social media habits. They are all on IG but none of them follow topics that I might fall into when they search. They really only go on there for their interest of food, music, make-up or humor. I was consistent on instagram for 2 months, with very little engagement from my audience. But, I also realized my audience will abandon social media for months at a time to focus on work, or just wanting to seclude themselves.

I am going to try some different tactics in IG, but I am not sure when I call it quits or when to keep being in the process of massive action. I plan to reach out to specific subscribers and get some feed back. I am also opening up my net a bit and going to look in to being more active in a few facebook groups, change my tactics on IG, and wonder what else there is I can be doing.

So, my two questions are when do I know when its time to change my niche or my marketing tactics (not sure if this is a marketing tactics or not)?
What tactics am I missing in seeking out my audience? I think this is a knowledge gap, but when I read, a lot is on social media. I am also wanting to start a podcast, but want to hear first form my audience that this would be useful.

Should I be looking at youtube and podcasts as a way to reach people?

Thank you!