Diagramming is a good strategy. I have used the Manhattan guide.
It is basically finding the conclusion and evidence(premise) from a given argument or passage with the help of keywords. With practice, you can create mental diagrams, which will save time !!
In CR, the following approach works well :
1. Read the question stem
2. Read the argument using the diagramming strategy(find the evidence and conclusion)
3. Jot down possible assumptions
Don't worry, practice more and more questions and try creating these diagrams mentally !! If you follow the above approach, I bet you will improve your timing skills for these type of questions !
Hope this helps !
"Success is going from failure to failure without a loss of enthusiam." - Winston Churchill
As vs Like - Check this link : http://www.grammar-quizzes.com/like-as.html.