From where to start verbal practice?

GRE Verbal Problem Solving
1

I had a diagnostic test score of 312 (163Q 149V)(official practice test 1). I have recently completed the first week of verbal videos.
Now, from where should I start the practice of verbal questions?

There are many source:

  1. big book
  2. Official verbal book
  3. gregmat questions

How and in which order should I start the verbal practice?

Your expert guidance is required.

Regards