My advice

FWIW, my advice is simple....

1. Write everyday. Doesn't matter what it is, just write. You'll get better if you just practice
2. Use your tools. Don't hesitate to look up a definition. New words are new tools
3. Get feedback from a wide range of sources and take note
4. In fact take notes all the time - carry a pen and paper or a PDA, something to jot down ideas
   
5. Write about what you know, or what you want to know
6. Research widely. Get to know your sources and your topic
7. Get out and about, see things, do things and write about them... whenever you can!
   

Writer's Links

Spend a few hours reading these links, then start writing. Easy. Read Aristotle's Rhetoric online at MIT, free. It's a classic and remains influential to this day. Try Writing.com, see what you think. It's extensive, anyway. Don't spend too much time hanging around reading, though. Why not write for kids? Or go freelance? Check out Googles' writing resources. You still aren't doing any writng, are you? Why not procrastinate here? More links, from Rutgers. Will it never end?

Myths and Legends

Myths and Legends - there's good writing material here. Witness Harry Potter and his ilk. You can walk in the footsteps of J K Rowling's research by trawling for historical material on Nicholas Flamel, Cerberus and the Philosopher's stone. Or just read about it here, in my new Mythoblogia.

It's more than a passing interest... I've been addicted to reading the Greek and Roman myths since I was a kid... and that interest has spread to the dark arts as well as comparative religion. So yet again I am demonstrating a method behind my madness. Write about what you love, or write about what you want to learn. If you can do both at the same time, great!