Begin with a simple sketch, just one or two blossoms, with the separate petals defined:Prepare two puddles of colour, a yellow and a red. I used Winsor Yellow and Cadmium Red with a bit of Quinacridone Magenta for variety of hue. Pre-wet one single petal with a wash of yellow.
While the yellow is glistening and wet, load up your brush with red (pigment-rich rather than watered down), and dab colour into the base and up the centre of the yellow. The wet yellow wash will start to take up the red, dragging it into natural-looking veining.
While that petal is drying move over to a new one, staying away from the first. Start with the yellow as before and add the red, observing the natural shifts of colour and leaving a yellow edge to the petal.
And repeat, again leaving the still-wet petals alone while starting a new one.
Fill in between the petals once they have dried, using the same yellow to red technique, and move on to the next flower.I added a little blue-green, a mystery mix left over on my palette, for some pockets of shading in the yellow.
Mixing Sap Green with the yellow, lay in the stems and a few leaves. Careful brushwork will keep the the red edges from bleeding into the green. And then go to town with an assortment of wet in wet green shades for background.
And that wraps up another two-hours-or-less painting. The studio cat, below, stepped between me and the tulips a few times, just in case I needed his input. Very decorative, if not helpful.