Start by getting the overall shape of the flower. Make sure you sketch lightly as you will want to remove any unwanted lines later.
Here I would like to mention a very useful tool for getting proportions right, it’s called the 'Proportion Measure' and is included within the full eBook.
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To continue next sketch in the petals once you are satisfied that all these are in proportion you can start defining their shape.
Next you can start on the detail but before you do so you can erase any unwanted lines, otherwise it will be difficult once all the details are in place.
Now you can render in some shading, this will give it a more three dimensional appearance.
Now I want to show you the different stages of producing a drawing.
But first here is an overview of the process.