Preparation, strategies, resources, errorlogs

I have been solving good number of SCs these days. I mostly go wrong when the given sentence is correct and does not require any changes. something always pushes me to think that the given SC question is incorrect. If no answer convinces me, I go on to read the choice A to check if it is correct. It works out many times when all the other choices are seemingly incorrect. But, problem arises when you have an answer which is damn close. As I am already thinking that the sentence is structured against the principles, I tend to choose the incorrect answer which is close but not correct. I think I need to start thinking that the given sentence is not always incorrect. If there is anyone reading this has anything to contribute, you are most welcome.