Good work Moko!
You have a good sense of form and self-colour already, it's part of your style. Allow me to give some ideas on how you could also experimen with environment colouration as well. This is a scene clearly lit by a blue sky. If you look at such a scene in reality you will find that all parts not directly hit by sunlight (i.e. all shadows) will not be dark red, but actually a mixture of the sky colour (blue) and red - i.e. violet. This is of course because the light coming from the sky (which is diffracted sunlight) is blue. Similarly, if you knew that the ground below the rose was green (such as grass), the flower would also catch reflected green light from below, resulting in those shadows turning a mix of red and green.
Here's an example:

(click for big view)
Note how the shadow sides of the sphere pick up blue and green respectively. Even the ball's shadow is coloured by the sky above (ground shadows are in fact especially coloured on a blue-sky day).
Adding environment colour is not necessary, but it's a nice way to add realism. Maybe something to consider for future experiments.

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Griatch