I don't know much about GRE tests, but I would like to say there is really no "tactic" you can use to get an high mark on its Verbal Reasoning. You will have to actually improve your verbal reasoning ability which will take some time, like a few months to a year to see any sort of noticeable improvement. What to do to improve it? The best way is to read and listen a lot. Read a lot of newspaper and magazine articles that critique something as they are full of such reasoning. Most nonfiction books also do that since they are all written to make a point on something, which must use such reasoning. Read lots of good texts attentively, looking up new words and phrases as well as any unfamiliar grammar. As far as I know, that is the only way. Resist temptations for those nonexistent "tactics" and do what is right. Even if you do not pass GRE on the next try, you will at least have improved your English somewhat.