Preparing an image for hand-tracing
Sometimes it's a good idea to edit a photo before using it as a drawing reference. For example, you may want to increase the contrast or apply a filter that exaggerates the borders between light and dark areas. It may also help to simplify things visually by converting a color photo to black-and-white.
I opened my flower photo in Photoshop, converted it to grayscale mode and used Unsharp Mask to exaggerate the edges. I resized the image so that it would fill a letter-size sheet and printed it on my laser printer.
Then I placed a piece of tracing paper over the print and made a pencil sketch, drawing around the edges of the flowers and leaves. I took some liberties with the placement of the flowers, moving the tracing paper around to different areas of the photo to get the composition I wanted. I drew over the pencil lines with a black felt-tip pen and then scanned the finished drawing back into Photoshop.