Ask HN: How to Write a GPDR Subject Data Access Request

With GPDR around the corner, what is the appropriate procedure to request data access from companies? I have made the experience that with a lot of these types of requests, using email or website-based contact forms will not yield an answer. On the other hand, I'm not eager to use a lawyer, since I'm mainly curious (and also want my data deleted!)

There's a difference between being right and getting right, so what is the best way?