Do you read your textbooks from A to Z? While it might seem to be the most thorough way, it is not the most efficient way. Today, we have dug up some older - but still equally valid - research from Harvard University.
Dr. William Perry, a psychologist and the Director of the Harvard Reading-Study Center, asked 1500 first-year students from Harvard to read a chapter consisting of 30 pages from a book. The students were then told that they would be stopped after 20 minutes, asked to jot down the essential details, and summarize what they've just read into an essay.
The 1500 students read the chapter and were, as promised, stopped after 20 minutes. They went on to take a multiple-choice test on the details of the chapter, in which they generally did well. But when asked to write a quick summary of the basic theme and purpose of the chapter, only 15 out of the 1500 students could do so.
Only 15 students had considered reading the summary to understand the overall theme of the chapter. Dr. Perry dubbed this "obedient purposelessness" and indicated that students were not reading, and thereby learning, efficiently.
Approach it differently
Skimming ahead and prioritizing what you read is not only completely fine; it pays off! It requires you to have (or develop!) the confidence to make judgment decisions. Dr. Perry had a brilliant suggestion:
Question what you want to get out of the reading you are about to undertake, then go on to skim for those points.
He also advocated for talking to yourself when reading, e.g., by asking, "Is this the point I was looking for?".
This might seem easier said than done - and it most likely is - but practice makes perfect. Look out for pointers on what the reading for the next lecture is about, and structure your approach hereafter.
In case you want to know more details of the experiment under discussion, you can read more about it here.