I have taken the LNAT twice; once in Feb, once YESTERDAY.
I scored 22 in February, don't know about yesterday obviously.
Focus on every line, but make sure you read continuously, JUST like you'd read a normal book or textbook.
If you focus on each line individually the paragraph won't make sense. Make sure it flows, because a recurring question on the LNAT is "what is the writer's main argument" which would only make sense if you have a general impression of the passage.
Don't sweat, and don't waste time on a question.
EDIT: and Umar, don't gauge time for each passage and rush yourself to finish each in 8 minutes. Just read it, take it easy, relax, and answer.