Aristocrat
Whenever i solve critical reasoning question, i am not able to find premise and conclusion properly
most of the time get confused between them, and therefore get inferred based question wrong.
Any idea?

Think of it this way: Some one is presenting his side of the topic in a debate. The topic is "Shut down all nuclear reactors now."
Say, the person is speaking against the topic.
Once he is done, what will you say is the conclusion of his argument?
His conclusion is the main point he was trying to make throughout his argument i.e. 'do not shut down all nuclear reactors'
What would have been the premises in his argument? Something similar to
"20% of our energy needs are met by nuclear energy."
"It's a relatively cleaner energy source."
"Very high safety stds are maintained now so Chernobyl like situation is very unlikely"
etc
Premises give you the data that the author/speaker gives in support of his conclusion.