Sullivang,
My suggestions for preparation for the Basic exam are as follows:
For the section on NDE methods, review as many Level II sample questions as possible. Spend the majority of your time studying in areas where you do not have experience, for example if you routinely do RT and MT leave those areas go and concentrate on UT, PT and ET.
For the materials and process section read "Materials and Processes for NDT Technology" (available from ASNT). Read it from cover to cover. This section of the exam is based primarily on this book.
For the SNT-TC-1A section, read that document (also available from ASNT) pay particular attention to which sections are "Shall" (meaning mandatory) and which are "May" (meaning optional).
For each of the method exams ASNT has a listing of reference material. If time is limited I found the best one book to read would be the ASNT Handbook for that particular method. The thing to remember is the questions have been generated from persons from many different backgrounds. Therefore, in MT for example, expect questions dealing with portable yoke inspections as well as horizontal wet machine inspections, as well as limited use applications such as swinging vector and multi-vector techniques.
Good luck !
JR97