I'm not successful much at those, but when I am it is because I have circled the difficult parts. I think it helps me remember where the parts are in relation to my pencil marks, so I can find or remember parts of the passage when going back.
Regarding the comfortable/successful distinction, I believe that the ... />
So, when the argument mentions "successful salespeople," it is talking about ... living in sales" can include successful salespeople, mediocre salespeople, even terrible ...