It's quite simple actually.

Start with a new layer
Draw a basic petal with an ellipse.
Colour it with a gradient. You could do whatever you want to make a single petal look nice.

Duplicate the layer.
Move the layer rotation point to one end of the petal (where the center of the flower will be. This is the only 'by hand' step. I put guides to help.)
Enter in a rotation value. (15 degrees for the first version, 30 for the other.)
- For the first version: Select the two layers, duplicate, move the rotation point again, rotate 30degrees. Do it again and now you have 6 of the 24 petals. Select all 6 and do it again with 90degrees. Then all of them and 180 degress. 24 petals done.
- For the second it's the same basic idea.

Now you need to get the petal overlap to look proper.
Create a mask for each of the last two petals.
Select the first petal layer and get a marquee around the whole petal. (I do magic wand then invert selection.)
Now go back to the last petal, mask out where the first petal is selected.)
Repeat for the second last petal.

On a new layer, draw a circle and center it on the flower. Done.


You could use this to make things that actually look good, instead of ugly flowers.

Instead of an ellipse for the petal, draw a more natural shape. Make a couple. The key is rotating them around the center point. You could also rotate a by hand for a slightly more natural look.

Just thought I'd share, in case there's any tricks in there that people didn't already know. I'm all about doing as little by hand as possible.

 

-----signature-----

One petal flipped. Then the same basic steps alternating the two petals.

 

-----signature-----

Neat, I'll have to mess with this sometime! Thanks