All of those are good ways to learn, but I feel that fantasy writers need to go further. We need to think outside of the box. Philosophy, literature, science...all of those are important areas of study. A large vocabulary is an important tool to have in the writer's toolbox.
But when you're writing fantasy, you need to know things that your characters might know. How do my characters keep their skin clear and free of blemishes (which will be important in The Bodyguard)? How do they treat wounds? What homeopathic remedies might have been available to them?
In a fantasy world, you can create plants and potions with their own properties, but I think it is better to bring in elements of reality whenever I can.
So I found a remedy that would slide easily into any of my stories: honey.
I won't expound upon the virtues too much here, except to say that I have started using honey for various reasons myself, and I have found that it works. So when I put honey into my stories and have Lakshmi putting it on her face like modern women would spread beauty cream, I can support it with my own experience.
And I believe my pursuit of knowledge, at least in this one instance, has been a success.
If you want to learn more about the uses of honey, and check out a truly great blog, go visit Crunchy Betty's blog and learn all about honey and the virtues of putting food on your face.