Take a sheet of watercolour paper from the block. You can stretch the paper but you don't have to. If you don't stretch it, it will curl up slightly but that's not a problem for this work.
We will work with Cerulean Blue 535 and Yellow Ochre 227. Apply these to your pallet. Use a medium-sized brush that can absorb a lot of water like no 8. Mix some of the blue with lots of water and loosely make a U shape with two dots underneath. Brush no 6 we will use for the yellow. Apply it to the paper and mix some sections with the blue paint while it is still wet. This is the wet in wet technique. Finally, the wet paint is accented with a no 4 brush and concentrated paint. This brush has a nice tip for applying details. You can see how the colours flow nicely into each other.
Once you are happy with how it looks, let it dry. If you have acquired a taste for it, just make another one!
Lastly, draw a circle in the work with a pencil. I always use a glass to trace. This way you can see where you want the circle to be and trace it neatly. We will later paint the metallic colour in the circle.