Not an expert, but here's my 2 cents. With Verbal, it depends on the question type. If it is Sentence Correction, then you need to look at the splits and analyze the choices vertically. Sometimes similar answers are separated by other answers, so you may need to look at answer choices A, C, & E together (vertically). With CR, I personally go through choices in the order that they appear, and assign a score (maybe the answer, probably is the answer, definitely not the answer). Then re-read to eliminate 4 choices and pick best one. Similar for RC except I first glance back at the passage real quick.
As for quant, I glance at answer for things like how far apart are they, do the answers contain variables, what kind of expressions do they have (squares, roots, etc). Then I solve and match my answer. I'm not the best at quant but I find this helps.