Your question actually includes two very different questions. I’ll impart first my suggestions on teaching a budding writer.
There’s a bit of a preparation phase (sometimes lasting well into the writer’s prime) that embodies the foundation for the skill and imparts nutritious experience for growth towards being a great writer. Make sure the budding writer lays a robust foundation at the outset. Teach good habits early (the basics are important, like good spelling, grammar, things to avoid, common mistakes, strength of voice and structure).
Even in my youth, my very literature-minded mother would always say “reading makes good writing”. That’s just a golden rule that should always be followed. Read, read read. Learn new words, learn styles, expand that vocabulary. Proofread and edit other peoples’ works. There’s TONS of places on the internet where the student can get his feet wet in a community of peers with similar situations.
Strunk and White’s The Elements of Style is a great item in the toolbox for any writer as well. Seek out resources on the web, there’s tons of great free stuff. As the foundation builds, teach them nuances such as alliteration, plays on words, idioms, metaphoric style, rhyme, abstract, free verse and even delve into poetry, journalism and all forms of perspective.
But for the actual writing process, the writer will likely have his/her own style and methods. Basically follow the tried and true “write what you know”, choose interesting topics, try challenging exercises and infuse the idea into the pupil to be his own worst critic.
Outlining is indeed an essential tool, and should be encouraged (although I know many writers that don’t do much outlining – but for me, it’s a fantastic method).
As for explaining it succinctly and learning to write a novel, specifically; you’re right that it’s not an easy task on either account. Perhaps the most important element of novel writing is to have a compelling story to tell. We didn’t blaze through the verbose and mind-shattering descriptiveness of JRR Tolkien’s books to admire his writing style, we all wanted to find out the fate of Middle Earth, the One Ring and the Fellowship.
Start with a great story, frame it properly to a fitting scale and setting, place all the elements of storytelling there in the proper order, and the rest is supplemented by the skill and style of the writer, but those things are learned through experience, reading and that foundation I mentioned earlier.
If I had to put it summarily in one sentence, I’d have to say…
The writer is simply a conduit for an idea, the novel is a result.
Whether it’s a good novel or not is a measurement of the author’s strengths… and weaknesses.