Help with Critical Reasoning Questions

Hi all,

I went through Manhattan CR guide, followed their approach but questions are not completing in 2 min time frame and I am not also getting all of them right. CR is pretty bad in a nutshell. I went through some of the discussions here and people recommend Powerscore CR bible.

I have below questions

1. Do we need to diagram as suggested in MGMAT guide?

2. Are there specific question types where diagramming absolutely helps? Are there question types where we can avoid diagramming totally?

3. While using Powerscore CR, I am assuming they dont ask to diagram from what I read in the forum? If so what do they ask to focus on in the whole passage or question type?

4. While going through Powerscore CR, if I had to make notes for each question type what is the easiest way to do that? Something that I could go over before taking any practice test and also before GMAT.

Please let me know.

Your help is appreciated.

Thanks