Speed Reading is the Key
Try some books available on speed reading.In the reading section you dont find condensed passages but rather those passages which have lot of non key words like articles (a,an,the),conunctions,prepositions,you hav to skim all those.
Also before you start reading any passage go through the questions and first lines of all passages.You will get an idea of what you have to look in the passage and what the passage is about.
Try to grasp the main idea of passage and each paragraph and the supporting explanations or idea. Just think when you want to convey some idea with some supporting explanations how you organise your passage.Either you give your main idea first and give sufficient explanations and examples in subsequent paragraphs or you arrive or deduce your main idea in the last and concluding sentence of the passage by starting with an assumption and giving arguments for and against assumption in subsequent paragraphs of passage.You can try books on paragraph writing.It will also help you in the writing section.