Keshav knows what’s up.
I tend to read the abstract, figures and captions, conclusion. Then i know if it’s worth really reading it, at which point i print it out and break out a pen.
if it’s really REALLY worth reading, ipython usually comes out to play, too
I'll just note that this pairs wonderfully with the Whitesides paper on Writing a Paper (https://gmwgroup.harvard.edu/files/gmwgroup/files/895.pdf), which is also required reading for my team members.
The same technique with necessary modifications is also applicable to figuring out whether it is worthwhile to completely Read a Book. These days Books have so much unnecessary filler that a lot can be skipped with no loss of information/knowledge.
PS: The same author has also written two great books on Computer Networking; 1) An Engineering Approach to Computer Networking 2) Mathematical Foundations of Computer Networking