Set up your background and texture.

In Photoshop, create a new file with your desired dimensions. Add a gradient layer by either importing my premade gradient or by making your own: Choose any three colors, set one as a Fill color, and use a Soft Round Brush with varying opacity to dab around the other two colors.

Add a texture layer. I use a noise texture PNG to give a grainy feeling to the image. Set its Blending Mode to Overlay and Fill to 20%.

Draw your base shapes.

Draw flat shapes for all the objects in your illustration to create a solid composition and ensure the focal point has a distinct silhouette.

Create a new layer and use the Hard Round Brush tool in grey to draw the basic outline of your main object. To draw my tomato with a clean line, I set the Brush Smoothing to 100%. I continue to use this brush and the eraser to refine the silhouette.

On a separate layer, do the same for any other elements of your illustration. I’ve done this for the leaves of the tomato.

Add color.

For base coloring, I always use a Clipping Mask with a Fill Layer so it’s easy to change the color at any point.

Create a new layer above the shape you wish to color, and then right-click and select Create Clipping Mask. I’ve used the Paint Bucket tool to make  a bright orange Fill Layer for my tomato.

Repeat this step for any other colors you wish to add. I’ve created a new Clipping Mask for the purple tones on my tomato and added them in using the edge of a very large Soft Round Brush.

Refine the colors.

After I’ve drawn all the objects, I play with the image’s overall color by adding a colorful gradient overlay. You can use the sample I provided or make your own.

Place the gradient overlay layer just beneath the noise texture layer. To add an intensity to the colors, I’ve set the Blending Mode to Difference and the Fill to 36%. Your image may need other settings.

Pro tip: To further refine the colors, I sometimes go in and adjust the Brightness and Contrast of the entire image, as well as the Opacity of some layers.

Add highlights and sharpen edges.

Think about where the light would naturally fall on your object and create highlights. Add a new layer above the color overlay and draw the general highlight shapes using the Soft Round Brush. Refine the shape and soften the edges with a soft Eraser.

Return to the shadows you made in Step 4. Select a hard Eraser with Smoothing set to 100% to create sharp edges at the base of the shadows, which gives the object the illusion of depth.