This is a 6" x 8" demo that I did in September as part of a private class that I was teaching. I am real happy with how it came out. I am always so relieved when a demo turns out well. It makes me look like I know what I'm talking about.
I was explaining to my students how to pre mix some colors first and then start blocking in all of the main shapes.

"Mountains Near San Miguel", 6" x 8" oil on linen, Frank Gardner © 2008
Private Collection
There were less than ten colors that I mixed up to represent the big shapes. I mixed those and adjusted them on my palette before I did any painting.
The main colors that I mixed up were:
1. Darkest color - Trees and a few triangular stacks in the distant field.
2. Lightest color - Clouds.
3. Brightest / strongest color - Flowers
4. Next brightest - Foreground grasses and plants.
5. Light source / sky - The sky would be the lightest value if there were not any clouds. I judged how dark in value to make everything else compared to this value.
6. Background mountain.
7. Mid distance hills.
There were a few slight variations on these, but basically that was it.
I adjusted these a bit on my palette until the relationships between them were accurate.
Once I had all of the relationships between those colors worked out it was just a matter of putting the right shape in the right spot.
The linen panel was not toned first and I laid in the yellow and orange flower colors first to keep them nice and clean. Notice how I massed them into groups and did not think about painting individual flowers and details. I massed together all of the other main shapes and values as best I could too. This is the basis for a strong design.
Once the shapes were all blocked in on the panel I made a few final adjustments. You may be able to see where I laid in a lighter color on the background mountains to adjust the color that I had mixed a bit too dark.
I got the kindest email from one of the women from this private class and I'd like to share part of it.
"Frank, painting with you on our terrace in San Miguel was just an incredible experience for me! Your art instruction was the best I ever received and I think if you'd been one of my art teachers when I started college, I would have stayed with an art major! You have a natural, easy style of delivering information combined with the ability to tailor it to not only the masses, but the needs of the individual, as well."
It makes me feel great when someone gets that much out of my teaching.
Giving art lessons, and trying to make sure that everyone gets what they need out of it, is one of the hardest things that I do, so it is nice to know when it works. Thanks for letting me know "R".
Here is one more new painting from last week.

"El Puesto de la Esquina", 8" x 10" oil on linen, Frank Gardner © 2008
$780. Framed. Available at Galeria Gardner
Edit note: I've removed some of this post to make it more compact for a repost of it Dec. 2010. Therefor a few of the comments below might be confusing.