guys , last month i had completed the powerscore CR bible , and had practiced questions from the exercises given in the book + some elementary OG 11 problems .... what im figuring out to my horror now is that when i was trying to do some toughies from OG 12 , i got a success rate of 75 % , and also my timing is screwed up

!! .... since im doing pretty good on SC and RC , CR is one point i desperately want to improve on.
The problem is that im trying to apply rules i learnt in powerscore to every question , but in that wasting a lot of time , and also it is not clear whether those rules can apply to all the questions

.... please tell me how to improve CR , and also what should be the ideal time I should give to the CR questions ?
any other signature techniques you guys might have applied would be of great help .
Looking to GMATClub to save the day again !