For exams such as the SAT and the GRE, passages are often cropped from the middle of a complex and arbitrary research report. You will be missing a lot of context. Standardized tests give you everything you need to answer reading comprehension questions. Read carefully--it takes longer to re-read. Realize that for timed reading assessments you only need to retain information in your short-term memory. You can refer back to the passage to answer the question. If the passage is not available while you are answering the questions, summarize each paragraph with a few words and note very detailed sentences. Technical details or direct quotes are likely to become test questions, especially if the rest of the passage is general. Acquainting yourself with the types of questions you will encounter is the most effective way to find the reading method that works best for you.
Reading news articles and journals is an excellent way to improve reading comprehension. News stories simulate reading assessments in that they lack context when they are continuations of previous headlines. Journals often use complex arguments that are difficult to understand, particularly if you are distracted. Learn to focus in any environment. If you can read and comprehend in the presence of noise, then you can read in a quiet room under a bit of stress. Use test preparation manuals to familiarize yourself with typical reading assessment questions. Ask yourself similar questions as you read news stories and journals. Note the organization of a passage, the tone of the author and the type of passage (e.g., persuasive, informative). If you can summarize the article and recall the details that stand out the most, you are on your way to succeeding on a reading assessment.