The first step to making a gum paste rose is to start with a base. This can be a small ball or you can shape it slightly to make a cone.
Then you make the first petal. The first petal I like to make particularly wide so that I can make a very defined curl in the centre.
To make the petal: roll out the gum paste and cut a petal using a rose petal cutter. Further roll out the petal to make it even thiner. The thinner the petal is the more it will look realistically delicate. Transfer the petal onto a spongey surface and using the large ball tool make small circular motions around the edges until they start to curl.
Depending on whether you need florist wire to attach your flower to the cake you would stick the wire into the ball now. If not, just start adding the petals to the base.
The first petal is attached to the base by curling it around it.
Next make a few more petals. These ones are smaller. The amount of curl on these petals is much more minimal. What is being made now (the center of the rose)has a closed rose appearance and so the petals have a stiffer, less delicate shape. These are curled around the base, covering the edge made by the last petal added.
The next petals made are what are going to make the petal more opened. These petals are larger and have a more defined curl around the petal edges (I like to think the curl reminds we of a billowing curtain).
These are made the same way as the previous petals but more emphasis is put on the curling and so use the ball tool for longer and I like to use it all over the body of the petal.
These petals are attached in mostly the same fashion but are flared out more so as to make the rose look more open.
This a half open rose. The more petals you add and the more you flare them produce a fully open rose. Typically when making an arrangement you might want to add a variety of rose styles.
Here's an example of open roses I made in the past for another cake:
(with these some of the petals were curled inwards using a toothpick)