Sentence Correction

Sentence Correction : How my mind works when I see a sentence correction question on the screen ?

1. I will read the statement - I read the statement fully including the underlined part(But I will not stress to understand the intent meaning of the sentence)
2. I will concentrate on the underline part of the sentence.
3. I will find the flaws in the underlined part of the sentence. (Flaws - How do you know it is a flaw ?)
4. I will check for the answer choices which is without flaws(which I had predicted)
5. If my flaw is/are never highlighted in the answer choice - I will try to find the flaws by comparing the underlined part to the answer choices with the underlined part in the sentence.
6. I will select last answer choice which I find flawless, concise, and no ambiguous. 

What are all things can go wrong in doing the above steps ?

1. If you do understand the intended meaning of the sentence, and esp. if you don't find the relationship between the underlined part of the sentence with the non-underlined part of the sentence - YOU SIMPLY CANNOT GET THE CORRECT ANSWER CHOICE FOR HIGHER DIFFICULTY QUESTIONS i.e 600-700 and 700-800 question levels.

How you should react for a sentence correction question, on seeing it on your screen ?