Shashi, everybody has sailed through the same boat. Trust me, reading all of those links will only cause you to panic, they don't suggest what you need accurately.
Typically, every question and problem in GMAT can be solved within the stipulated time limits. Provided, you identify the trap as early as you could and you know how to get to the solution quickest. If you are taking longer than a minute on SC, it means either your focus is bad or you are not even equipped to identify the trap.
LEARN the Traps and stop worrying about speeding up and the time management for the time-being. Read
MGMAT series, Powerscore for CR etc, solve questions from anywhere around the world, especially the 1000 series are good practise. Learn to identify the traps quickly and learn to improve correcting them quicker. As you go, you'll notice a profound difference in your speed automatically.
GMAT is a template based exam, if you know the templates, you are good to crack it!!!! All the best prepping.