My mentor once told me that his #1 piece of advice for success in graduate school in Clinical Psychology is to read and write a lot (of scholarly work, of course). This makes sense to me.
To be an expert in your particular field, it is important to have read every book chapter and journal article on your topic of research. You should be aware of the latest and greatest in your literature topic. It is hard to create something without first becoming a master of the topic. By taking the time to understand the latest and greatest literature in your subject area, you will be best positioned to make significant contributions to your field.
Of course, this is incredibly hard. It probably involved reading at least 50 pages of scholarly literature a day, and at least 2-3 hours of extra daily work (and hard work – the kind of work where you can’t have any distractions). Most people don’t do this. However, if you can accomplish this early on, you will have a major advantage over everyone else.