How to draw a yellow rose

How to draw realistic flowers with mixed media on gray paper. Drawing of a yellow rose by Marcello Barenghi http://www.marcellobarenghi.com
Final picture: http://www.marcellobarenghi.com/2013/05/yellow-rose-drawing.html
Music: "hometown-hero" is royalty-free music from Free Stock Music http://freestockmusic.com
Materials used:
heavyweight gray paper,
9B, 7B and B pencils (Caran d'Ache grafwood),
paper stomp,
Ecoline,
colored pencils (Caran d'Ache Supracolor Soft Artist),
fibre tip pens (Staedtler Noris Club 320 Double Ended Fibre Tip Pens),
markers (Tria Letraset),
pens (Pitt artist pen Faber-Castel),
tratto marker pen S black,
black and white acrylic (Decoart and Pebeo).
Time taken: 3 hours and 27 minutes