if you have a lot of time to waste, just read a lot. for example there is a tpr list with those books about "story of civilization" and history of art,etc. if u spend a year in the library and finish it, your score is guaranteed to go up. of course if you never read books in middle school or high school, it's unlikely you'll suddenly be able to go through this. otherwise i can say verbal scores are often unstable becasue the tests are always different and may vary from 8-12 for someone whose true skill level is at 10.