I don't do that kind of painting however with any painting you look at the different colors and the shapes of the color in the flower and try to reproduce that. Don't look at the flower as a whole but each pedal individually. Sort of like painting by numbers without the numbers. Make a pencil sketch first and then fill it in. I sometimes either take a photograph or a sketch and make it full size of the painting and transfer it to the canvas with carbon paper. Photographs, I run them through photoshop and make them 16"x20" which is the size canvas I use and crop it into 4 different images and print them with my computer printer and then past them back together so they are the right size.