It all starts with a good drawing. I found the centre of the plate and measured out from there to the outside of the circle, many many times. You can see the darker tick marks. Joined them together and paralleled the other line. The rest of the bowl is much more complicated, but this will do for now.
I like to make a loose grid, dividing the picture in half both ways, so the drawing will be fairly accurate, yet still look spontaneous.
The grass surrounding the plate will be drawn later. No need to smudge it now.
I painted yellow everywhere there is yellow, just to get a sense of which yellows to use. I used everything from lemon yellow, to cadmium yellow to New Gamboge and Quinacridone Gold.
Because the painting is 50cm (almost 20") square, I am choosing to paint a quadrant at a time. I rotate the painting, working on the part closest to me. Not too fond of using an easel if I don't have to. I only used it for drawing to get the scale right.
So, we are into reds now. The zinnia near the middle should probably have been a more translucent red, but I used Cadmium Red Deep and Cadmium Red, plus a little Winsor Red Deep. They are fairly opaque colours.
The lily was brought to life with one of my favourite colours, Opera Rose. After layering a thin base of a mixture of Alizarin Crimson and Cadmium Red Deep, I went back in multiple times with various reds to colour and darken the petals. Finished with Opera Rose which does a great job of brightening any red under it.
The periwinkle blue Clematis with its white stamens has been a fun exercise in laying down glazes. If you look at the top and right petals, you will see the first layer, a combination of Opera Rose and Cobalt Blue. I kept it fairly wet and sprinkled some salt to cause those little white specks to happen. I'll now go over with multiple layers of different ratios of those same two colours to create the look of the other two petals. I think they are looking fairly realistic, almost papery in appearance.
The only colour that I didn't have to mix was for the browny yellow lily that you see to the left and under the clematis. I used Quinacridone Gold for that brown colour. Easy peasy.