Definitively start reading the economist ASAP. I read about 2 articles a day, everyday! It has helped me a lot. Make sure you understand what you are reading. Make note of authors VP and things like reffential phrasing.
yeah i say other than cases of without like the one you mentioned and the word when in the context of referential phrasings, the key words work very well.. and suggest sticking with them.
jdawg's approach was the other route I imagined possible... but I hesitated with that approach only because the grammar trips me up with this particular phrasing (aka, the lack of a comma). Good to know!
Ooh yes, be careful with NA. There is no "trick." Over time you will get better at pre-phrasing the gap. I believe having a firm grip on the gap in addition to the conclusion is the key to these questions.