Start with a tightly wound center that's like a spiral rose center, then start expanding the center by adding a row of loosely spirally petals that extend out. That will form the center part of the flower.
The next row of larger petals will curve up toward the center, and there should be 6 of them. These petals were wired on the one that I made so that I could move them around. They should be attached to the center so that they fall slightly away from the spiralled center.
The next row is going to be the same size or slightly larger petals than the last row, and are also wired. They should be curved DOWN, away from the flower. In some varieties the outermost petals tend to curl up so much they look like they're tubular because they've curled up onto themselves so much. They should be arranged so that they're staggered with the first wired row.
In general, you just want to give the look of a tighter center with two rows of looser curving petals outside of that. The outer petals are distinctly separate form the inner center, unlike a rose, which is more compact.
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com