Bad Flower Photography
A snapshot taken at a distance might be useful for observing an arrangement, but lacks the detail for a successful drawing. To avoid having to draw from an image like the one below, take extra closeups.

Bright Light
The intense, flat light from a flash can severely wash out colors and obliterate detail, as can very strong sunlight, especially if you have an automatic exposure being affected by dark areas. Natural, indirect light is best for getting plenty of detail in yor photographs. However, cameral film isn't as flexible as the human eye, so you may need to 'bracket' your exposures. Find out how to ajust the manual settings on your camera so that you can take three shots - one under exposed, one at 'correct' exposure, and one over exposed. These will give you the detail you need in highlights and shadows.

Subtle Variations
The camera doesn't always capture subtle variations in color, but then, neither do your pencils. Don't be afraid to use darker or ajacent colors to create dramatic effect. In this example, you might only see a range of two or three pinks; but look again and notice that you can add purple to the shadowed areas, light blues in pale areas, and overlay warmer reds with magenta to create variation in the petals.

Attention to Detail
At first you might think of this flower as having cream-colored petals, but on closer observation, you can note the hint of green showing through the transparent outer area, denser cream at the edges and center, and slight veins of darker color radiating from the center.