Reading literature is the most important.
It helps you to keep up with the latest in research .
Even though you don't understand everything at first, you can get an overview of the current research trends.
Side by side , it is also very necessary that you go through the basic concepts and the material directly related to your research (as there are lot of things to do and you can't do them all).So, reading books is also necessary.
Extensive and meaningful research will involve both of these.
With time, definitely you can delve deeper into the subject and the research becomes more and more exciting !
Regards.