Why kids like fire cars? Because they are red!
Red is a wonderful color in a painting, it attracts immediately the attention, even little small spots, I usually put tiny red spots in eyes, ears, nose and mouth when I do portraits, the viewer eyes will connect these tiny dots and wander around all the face, making the painting more interesting. This trick I learned from the wonderful artist Anne Watkins .
The last time I was in the Fire Station they told me that Saturday mornings they take out the cars to clean the station. I couldn't resist such an opportunity so I went there very early, no matter the weather was very bad. At a certain point it started raining and drops start falling on my Moleskine. The pen stopped working (maybe because is water-resistant?) So I ran to find shelter at the bus stop. There, while waiting for my bus, I finished the painting with red watercolor.