Fantasy author Elaine Isaak's book THE EUNUCH'S HEIR takes up a generation after her first novel, THE SINGER'S CROWN.
I don't believe you can get the full measure of any man, especially a hero, until he has been significantly tested. Courage is not the absence of fear, but going on in spite of it—in spite of what may happen. For the hero, this means trial and often tragedy in order to attain their goal. If they haven't striven for it, would they truly appreciate it? For the reader, (I hope) it means living with that fear as well. They know they cannot count on the hero emerging unscathed, and so they must be equally vigilant in their experience of the book.
The Singer's Crown grew from 3 sources: The first was a name I heard on my job at Ames Department Store, an intriguing name (which I had mis-heard, of course), therefore I hung onto it for years until I could figure out who he was. At the time, I was reading a variety of SF/F magazines and becoming increasingly irritated at the number of times the hero would jump in the sack, as if sexual virility were the key to the hero's identity. I wanted to create a hero for whom that was not true, a commentary on the sexual nature of heroism and of man. These two things came together when I saw a PBS program about the history of opera, and learned about the Castrati, singers of extraordinary talent who were castrated at an early age to preserve the voices that many of the time considered divine.
When I finished the first book, I had no intention of doing a sequel, never mind a series. But once I struck upon the title The Eunuch's Heir, I couldn't let it go. It raised the opportunity to explore similar issues from a radically different point of view: the all-too-human prince, apparently denied his spark of the divine, who responds by shunning his potential and becoming the beast they believe him to be.
In the first book, I created the world as I was working, which is, I believe, one reason why it took so long to write. The second book is where I discovered research rapture. I wanted to go deeper and develop some of the ideas inherent in the world I had spontaneously created, as well as building a more believable milieu. I read up on astronomy, medieval medicine, the ayurveda, mountain-climbing, Persian mythology and the Book of Kings (after viewing an exhibit at a local museum of Persian miniatures and illustrations). All of these blended together with my recent trip to India to enhance the experience of the world, and of the new nation of Hemijrai.
So my advice would be two-fold. Read as widely as possible outside the genre. Read subjects that attract you, then add to them with specific research for the work at hand. Build as much as possible from an understanding of the real world in order to create an authentic secondary world.
Then, when you have found all sorts of gems you'd like to polish into a stunning whole, brainstorm the possibilities and meanings of the facts or images you'd like to work with. How did they come into being? What do they imply about the people who created them, who must use them, who must live in the context you envision?
Research and invention should work together to forge the illusion of a complex world that spreads out for miles and centuries all around the reader.
Elaine's website can be found at http://www.elaineisaak.com