I was watching a show on TV where they were making a wedding cake, and I thought, "I can do that". And I so I did. I'll post a how-to the next time I make a cake. Hope you like it :)
You will need to gather your materials, and use a frosting nail. You can either use a small square of wax paper stuck to the nail with a tiny bit of frosting, or you can follow the last step in this tutorial to get the rose off the nail.
Load your frosting bag with the color of frosting you want and put on a rose tip. I like to used the tip with the wide part on the bottom. This makes the petals look thinner and more realistic. Make sure your frosting isn't too thin or thick. To begin, make a small glob of frosting. Try to make it vaugly cone shaped.
Next, while slowly spinning the nail and holding the tip at an angle, add frosting to make a taller, wider cone, about an inch tall. The top should be left "open" (you'll know what I mean when you do it) to make a small tear drop shape. This will be the center of your rose. (Click on the picture for a closer up picture)
Next, at the top of the cone, make a small arch shape, only about 1/3 to 1/2 of the distance around. Turn the nail around, and do the same on the other side.
Move down the cone a little bit, do the same, making the "petal" a little longer. Try to overlap the ends of the smaller petals with the new petals.
Keep adding pettals, from top to bottom, and each time, angle the top of the rose tip a little farther away from the rose.
You will need a pair of kitchen shears, or regualr scissors, if you didn't use a small piece of wax paper. Put the blades of the scissors on the metal of the nail, on either side of the rose. Make a quick clip, or it will tear. Use the scissors to put your flower on some wax paper to set and harden a bit, or put it directly on the cake. Have fun :)