I am going to colour this blackberry using pencils from my Castle Art 72 set. You can use other brands and similar colours though. To start with I will do the berry part and then finish with the leaves.
I start by doing a fairly pale background in a light purple shade. I will use Lavender.
I then take a darker shade and start to build up the colour. I will use the Purple Lake Deep for this and build up colour around each individual circle leaving a small gap in the centre for the lavender to show through. I tried to make the colour darker on the edge of the blackberry and lighter towards the centre by applying fewer layers and less pressure towards the centre.
I then do a similar thing with a darker purple and in this case the Mulberry. I do try to keep it much closer to the edge though this time.
Lastly, I use black. You will need to decide how much black you want to use, whether you want to enjoy the lush purple colours or have more black. I have decided to just use a minimal amount of black to try to give the impression of shadows between each of the individual parts of the berry. I, therefore, coloured just over the black lines that were already there to emphasise them.
With the leaves, I feel that a more blue/green shade looks better with purple shades and so choose something that I feel will work like that. I pick a couple of shades. I, therefore, start with a layer of phthalo green.
I want a darker shade to finish so I have picked the Viridian. I add some darker tones on the edges and near to the berry. I have also added a little at the bottom of the stalk to complete the berry.
Purple Lake Deep
Miniature Enchanted Forest – https://amzn.to/37qkCup
Castle Arts Soft Touch Pencils – https://amzn.to/37rocok
I also have some video tutorials which include blackberries that you might be interested in looking at.