You can find some really good resources for math test prep in the used bookstores in a college town. Some examples that I like are: (1) Humongous Book of ______________ Problems (fill in the blank with your math topic); (2) the REA Problem Solvers series; and (3) the Schaum's Outlines. If you don't live near a college town it might be worth a Saturday trip just to buy books. Alternately, all of these are available (used) through the Amazon Marketplace sellers at really low prices.
You should preview each title of these book series that you might be considering to be sure you like the authors style. Each one is different. You may like one series' treatment of Pre-Calc but prefer a different series for Calculus.
So how do you use these books ?
They are an alternate resource for explanations of basic concepts and problem solving techniques. You should use them as 'hint mills' and sources of problems to make up your own practice exams. Sometimes you will need
to flesh out their problem solutions. Remember, it's not about the right answer, but being able to find your own correct path to the right answer.
BOTTOM LINE: Always prepare for exams by making up and taking practice exams of the same length as the real exam in the allotted period of time. If possible, take your practice exams in the actual room where you'll be tested, and sit in the seat you'll be sitting in. Recreate the noise of a room full of other people taking the exam.
So, having done this, you aren't really taking the exam for the first time when you take it.
Have someone else grade and critique your practice exams. Be sure to always include some problems unlike ones you've solved previously to maintain a level of realism.