As you’ve already likely experienced, inspiration happens when you press your mind into service, and then step away to do some mindless, routine task. That’s when your best ideas will be generated. So, if you've worked hard, done the research, pressed your mind into service and you hit a wall, my advice is: go procrastinate. I'm quite serious about this.
I remember reading about the locations where the biggest scientific discoveries were made: the bed, the bathroom and on the bus. After a scientist had pushed and pushed to reach a solution, the answer manifested when she was mindless, about to snooze, having a bath or in a trance on the bus. The same principal holds true for writing. Do the research, do the thinking, then step back and relax. It’s in our restful, mindful state where the best ideas surface.
I don't spend all my writing days cloistered in my office. I do my best writing as I take walks, do the dishes or work in the garden. I get my best ideas, lines, whole paragraphs, and sometimes whole sections, word for word, when I’m doing some physical, repetitive, and mindless.
So, if I run into a roadblock while I’m writing in my office, I’ll get up and go for a walk. Sometimes just getting up does the trick and I just make it out the door when the eureka! moment strikes, and I run back to my office to write.
I've had students comment that what keeps them working towards the end of their project is the challenge of finishing the damn thing. That kind of "stick-to-it-ness" is commendable. But what will really carry you through to the end is fun: a sense of play, a sense of discovery, the thrill, and the mystery of this process you're engaged in. In my experience, "discipline" backfires: my subconscious, at least, is a toddler that does not like to be told what to do.
So, research, interview, experience, sit down to write. Write every day until it becomes habit. Once you’re there, writing will flow so much more easily. Then step back and do something mindless and the ideas will be there for you. And most of all, make writing fun, not work. Play!