You may want to consider taking the Snap on an iPad or Android tablet if you have access to one. The large screen on these devices will allow you to draw with much more detail than on your phone, and will look very sharp when viewed on devices with smaller screens.
On Android, the color slider will expand to show each distinct color available. On iOS, the color slider is a gradient rainbow, and slowly dragging your finger on it will allow you to see all of the different colors. On iOS, drag your finger all the way to the left side of the screen to select White, or all the way to the bottom of the screen to select Black.
By using a stylus on a tablet, you can have a large area to work with, and a detailed tool to draw with. This can lead to some truly amazing drawings.
