hi there and welcome to the forum.
get the OG and do all verbal quesitons there. also get kaplan verbal workout and pr verbal workout as well. you may consider some LSAT material - it is excellent for CR and RC. go throught the verbal forum on this website there are tons of good cr, rc, and sc questions every day. it is an invaluable resource for your gmat prep so use it to its fullest extent. the best part is it is FREE, so dont linger and despair, utilizing this forum + OG + the above mentioned materials will help you improve. of course given the fact that you time yourself and do blocks of 41 questions at a time, without a break simulating the real thing. this is the best advice that i can give - practice makes perfect. good luck on the gmat and the apps.
kayser