I make no claims for intelligence but I like studying. I am busy writing a book at the moment and have reference books strewn about, numerous web pages up, my tablet ditto, which gives you a clue how I do it.

You have questions you need to answer for your exams, teachers and readers. To answer these questions you summon up your experiences, and/or read around the subject until you have it clear in your mind. You write down the answer to these questions. Then you question your answers. This called critical thought and is where intelligence really comes in.

This all very well for things you are interested in, but when you really have to address stuff you don't particularity care for you have to slightly adapt your strategy. What is the question? What is the minimum you have to do to answer this question? What is the easiest way of doing this minimum (intelligence helps mightily here)?

Your first question is how do you study - therefore read around (books, web) and then come up with an answer that works for you, question it, carry on.

Hope this helps. Practice is everything here as elsewhere in life.