I have been learning IM, but still have to implement

I have completed many courses from website creation to social media strategy but find it hard to implement what i learn. I have been working lately. I am confused with niche ,i don't know wt to look for in the niche. i am personally interested in emotional abuse, support and self help. please guide me with what to chose and wt look for in a niche. I would also like to mention joining this forum has made life easy for me