I'd have had better luck controlling the color if I used Quickshape, but you can also continue to hold down and drag left or right to adjust the ColorDrop threshold. Sometimes if you use ColorDrop, you might notice that it 'spills' on the whole canvas.

The color will either fill your whole canvas, or work around the shapes you've already placed. Drag the color to where you want it on the canvas and let go. To use ColorDrop, choose the color you want from your palette, and tap and hold on the color circle in the upper right corner. The Procreate ColorDrop feature acts like the bucket fill once did on Microsoft Paint. This tool is also helpful when you're trying to achieve a smoother blend. With the eyedropper tool (which is also customizable in gesture controls) you can hold down over a color to pick it up, or hold down, drag and zoom to get more detail in your use of color. One of my favorite parts of Procreate is how much you can customize the colors you use, and in such detail. You can also use New from File or New from Photos to use a premade palette from another artist or generate a palette from a reference photo.

New from Camera opens your iPad's camera and lets you capture a color palette by snapping a photo. When you tap the '+' you can also choose New from Camera, New from File or New from Photos. If you go back to the palettes tab, you can name it or delete a palette if you don't need it anymore. If you change your mind, tap and hold on a color to delete it from your palette. To add colors to the palette, just select the color you want and tap in the palette box to keep it.

Beginner procreate