hey kim!! when are planning to give OTR? am planning to give otr in dec.. what i would suggest u to do is, study ur basics from any one of these books, Trombley, Willard or Pedretti. once u are done , start with ur Rita and once u finish with Rita, ull know what topics u need to prepare more and again back to the text book(study trombley..W..P...)
Before giving the exam u need to be thorough with Rita(atleast 3-4times). this is what all my frends did and they all cleared in the first attempt...
good luck and keep in touch..