Three passes, not one

Reading a paper start to finish, once, slowly, is how almost everybody is taught and it is the least effective method available. Three passes work better. First pass, five minutes: title, abstract, headings, figures, conclusion — enough to decide whether to continue at all. Second pass, half an hour: read for the argument, skipping proofs and method detail. Third pass, only for papers that earn it: the detail, closely, as though you had to reproduce it.

Most papers never get past the first pass, and that is the point. The skill being trained here is not reading. It is triage.