How do I identify the Qs that I can do and that I can't do?

Those questions pointers that you stated are great Vikram! I asked myself those same questions, but had never articulated them and instead just mentally thought them through.

Verbal is different because you have no formulas as you pointed out, but the structure and nature of verbal questions lends itself to the same kind of analytical breakdown:

1) What is the topic? (CR, RC, SC)

2) Am I good at this topic? Is it a strength or a weakness? If it's a weakness, I may need to jump ship.

3) How far along am I in the test? If I'm on question 38, then I know this question will be near the upper boundary of my limits.

4) Do I understand the passage or sentence? This should be clear.

5) Do I understand the question stem and what the question is asking for? If I don't understand the question, I'm in hot water.

6) What are the premises? What is the conclusion? [for CR] You need a good understanding of how the passage is structured in order to weaken it, strengthen it, etc.

7) Do any errors immediately jump out at me? If not, can I find some after 10-15 seconds of analyzing? [For SC] If after so many seconds of reading, rereading and analyzing, I still cannot see the errors, then another 30 seconds won't help.

8 ) Can I find, in the passage, where is the relevant material is that the question is asking about? [For RC] If I can't find the relevant material, I won't be able to answer.

Cheers!