One way to avoid frustration is to set a goal for yourself before you begin: determine why are you reading this paper or what you hope to gain. If you are a student or recent graduate, consider reading papers with the intention to get the most out of them. For example, if you are interested in results or methodologies, then focus your attention on that specific section of the paper.
My advice is to split the reading process into the three phases discussed below. While following each phase, keep checking yourself for reading comprehension and don’t forget your original goal for reading this particular paper.