Often when taking a test that has a Reading section, you become bogged down in the unimportant facts within the passage. Understand that reading for a test isn't the same as reading for personal enjoyment. The author of the test is seeking the test-taker to extract certain information from the passage. A trick to practice and pass the reading comprehension section of your exam is to read the questions first. Now that sounds crazy but trust me, it works. Think about it this way. When you read a passage first, you don't know what the test writer wants so you have (A.) wasted 2-3 minutes of your time by reading the passage first, only to have to retrace your steps after you read the questions and answer choices. Remember, you don't have all day to complete the exam. So, the trick is to read the questions and answer choices FIRST then read the passage.
Now that you have read the questions and know what the writer wants, become active. What does that mean? Use a pencil and become active on the passage. For example: circle words, cross out sentences, write the question # that you see an answer to, write "main subject", etc so you remain focused and it helps you remember the answer choices. Being active also helps you to not re-read a sentence. Let's be honest...test taking can become a snore and test writers know this.
With those two tips, you should be able to help shave off a few minutes on your test time and have a better chance at scoring a higher percentage. Remember, Reading sections of a test isn't for the test-taker (you) to gain breadth of the subject matter but to be able to correctly answer the questions in a short period of time.
Hope this helps!