A big learning curve for graduate students is reading the literature. I’ve seen student spend hours and days reading every single word of a scientific paper. And this is a good exercise for class, to learn all the parts and see all the things that you don’t know. But when you’re preparing your own research, this is no way to learn about an entire BODY of research and how your own project is related. Saying you have “read” a paper is not very meaningful, unless you can specifically cite a point in that paper that supports, corroborates, or conflicts with a hypothesis, method, or finding you wish to pursue.
So it is important to understand the difference between reading a single paper for the sake of learning about science, and what I call “reading with a purpose” for designing, conducting, and interpreting your own research. When you have specific questions that need to be answered, you don’t have to read every single word of a paper but it is better to understand the entirely of what has been done that is directly and indirectly related to your research. Remember that as you progress in your research you should expect to go back to some papers over an over again to check out different details relevant to your work, and you will develop a deeper understanding of it.
When I’m preparing for a grant especially in a new area, I like to do a search for relevant papers and sort them chronologically. Then a quick perusal of abstracts and citation metrics can help me understand the development of the field and key papers. One I can see the big picture, I hone in on critical papers establishing research questions and finding, and don’t spend much time on those that are subsequently filling in a single detail (most of them are like this). I keep notes on each paper, as relevant to the arguments that I would like to make, and the kinds of methodologies and findings that I can cite that paper for in my documents. You’ll learn to identify papers as Author, Date, Journal, which is the shorthand scientist use to communicate that they understand a particular line of research. Learn to associate key finding with those citations and also figure out what labs they come from (usually the last author). If you make a statement in a grant or paper, it MUST be substantiated through the citation of relevant literature. You’ll develop a set of a couple dozen papers that are most important for supporting your research based on the strength of prior research, as well as for establish the gaps that you will fill.