Paper is the most important way for researchers to get information, a typical researcher spend hundreds of hours every years reading papers. When you attempt papers in unfamiliar field, because of the lack of background knowledge, it's hard to finish reading at first. You should looking for survey paper or review paper as preview. 

For efficient reading, instead of read in order, you should get a rapid pass, and pay attention to the abstract, introduction, section titles, conclusions and references. After this you will know whether you need to read this paper, and which part attract you most. Then for the second view, you should figure out writer's proof, judge its worth, and mark the critical point for further read and use. After all, you can make the third view, come back to the technical details and take what you need. Remember, researchers read paper for use, define concept to explain further theory, all the read based on your requirement, when you really need the idea, try to contact with writers, that's the most efficient way.

That's all, thank you.