Artist Rob Alexander has illustrated 131 Magic cards. He's been around forever and he's probably done some of your favorite cards.
The first step of the creation of a card's art is its art description. The art description tells the artist what the card will do, what its flavor is, and what the mood of the illustration should be. Here were the instructions given to Rob for Vastwood Zendikon:
Action: Look at the "forest reef" concepts on pg. 19-20 of the style guide. Now imagine them coming to life as a huge "forest elemental," a gigantic creature made of stony reef lattice with "skin" of green shrubs and lichen, and limbs made of twisted landforms. Perhaps it has torn up a crater's worth of dirt, roots, and a small village as it lurches to its feet.
Focus: The huge forest-reef-creature
Mood: The land has come alive -- and it's not happy
The next step is for the artist to submit sketches of his or her vision of the art description.
Here's Rob's initial sketch, for which he used the first option in the art description.
Vastwood Zendikon | Sketch by Rob Alexander
The creative team liked it, but wanted to make sure that there was a creature clearly implied in the final version.
Vastwood Zendikon | Illustration by Rob Alexander
And here's the card in its final state, as you'll see it in booster packs of Worldwake in a few weeks!