1 Begin with line drawing.

2 Start adding yellow on the side the light is coming from using the Round brush

3 While yellow is still wet, add Scarlet Red to the left of the Yellow.

4 Using a stylus or blunt pointed object, begin bruising in the lines to as shown

5 While still wet, begin dropping in Aliz Crimson primarily towards the left but can drop in other areas for variation.

6 Without cleaning brush, dip into the French Ultramarine and drop (by just touching the point of the brush into the wet paint) at the left side of the berry strategically placing around those areas to help define shadow between the little bumps in the berry.

7 Allow the berry to dry but you want this still damp so some of the green will run a little into the top of the berry.
Add a little yellow in the leaves where the light would hit them and immediately pick up Sap Green, drop in, and paint the rest of the leaves.  While wet, pick up the Perylene Green and drop in on the bottom for shadow.
Repeat the same with the yellow/greens to paint the stem.

8 Once everything is dry, pick up a little French Ultra mixed with Aliz Crimson and add shadows between the bumps by dabbing a little color, cleaning off pigment on brush, and running the tip along the bottom edge to eliminate a hard line.  Do so more around the center of the berry and towards the left.

9 Once dry, use a clean damp slanted brush
(or you can use the round) and lift highlights on the right of several berries on the side the light is shining. 

10 If need be, use the Fr Ultra and Aliz Crimson mix and define more of the areas you wish to show in shadow.