Reading for school, or rather, reading for the purposes of educating yourself, is quite different from reading for pleasure. Reading for pleasure is done purely for entertainment value while reading for education, or researching, is done to further your knowledge of a subject with the aim of using it for something else. Many careers, such as real estate, banking, insurance, law, politics, and history require excellent reading retention and research skills to be successful, so it behooves you to learn how to do it well. You may think your chosen career won't require you to be a good reader, but like math, reading has infiltrated every career from electronic design and manufacturing to being a nanny, so you can't get around it no matter how hard you try.
The most important thing to remember about reading for school your goals and the methods you use to achieve them are different from other kinds of reading. When you read for pleasure, you read more quickly, aiming only for a general overview of the material that will help you visualize the story or subject in your head. Reading for school requires a more dedicated focus and attention to detail because you must be able to retain and make use of the information you're taking in. Many people have a ritual to get themselves into the right mindset. Some listen to funk music to get them in the mood and make the subject seem less dry, others need total silence in order to focus. Experiment with methods to find one that works for you.
In order to get the most out of your school or educational articles, it's important to read them with a specific goal in mind. For instance, if you're researching home health websites with the intention of hiring someone to help you care for your ailing grandfather, you should focus on the parts of the articles that are pertinent to you. Skim over sections that focus on stair lifts for wheelchair bound people or the history of society's perception of disabilities and zero in on the information you need: whether they bathe people, how they do it, how well-trained their staff are, and how much it will cost.
In school, especially in the lower grades, they will train you to do this by giving you a set of questions you must answer on your assigned readings. Many people will read the article first and then attempt to answer the questions, but you will have more success if you read the questions first. That way, facts pertinent to the questions will jump out at you while you're reading rather than you trying to rack your brains and remember parts of the article that didn't seem important at the time after the fact. For instance, if your article was on real estate and one of the question was 'which houses for sale had an attached garage?' don't you think it would be easier to look for the answer before rather than after?