In the early 1990s I was working for a grocery company making many hand drawn, cut and painted signs using fomecore board , Crayola markers (off of the shelf) , giant Pilot sign markers and Design Master floral spray paint. I routinely travelled to about 15 different stores with a case of fomeboard and my bag of markers and made whatever signs each store needed for displays and promotions. You could tell when I was in a store by the smell of the markers and spraypaint!
The Artist's Guide to Sketching by James Gurney and Thomas Kinkade and what a prize it turned out to be! I had never heard of either artist but their generous information and practical instruction allowed me to learn things that had seemed out of my reach prior to that. I started carrying a sketchbook all of the time and enjoying the world in new way. Later I was introduced to the Dinotopian art of James Gurney and to the nostalgic images of Thomas Kinkade.
Now James Gurney carries on his great tradition of learning and sharing n his wonderful blog, GurneyJourney.