You got the process wrong. It is not: first I figure out a subject, then I do deep work, it is the reverse: you start with deep work and go, step by step, into

You got the process wrong. It is not: first I figure out a subject, then I do deep work, it is the reverse: you start with deep work and go, step by step, into your subject. This does not mean you can not change direction, but the deep work is required before you carve out your niche.