I just started my Ph.D. and am trying to participate in a couple reading groups. Often, these groups will cover 2–4 papers a week. Upperclassmen seem to have no issue staying up-to-date and informed, but it typically takes me 2 hours minimum to digest a paper and probably something like 3–4 hours to really start grokking the equations. How can I read papers more efficiently?
I assume part of the answer is just practice. After a while, I will get faster. But are there any habits I can form now that will help?