Many images can be improved significantly by using a small amount of fill in flash to eliminate harsh shadows. The use of fill in flash will give a more diffuse and even lighting.
The image of the rose above was created using supplementary fill in electronic flash to give the image more even lighting by filling in the darker areas and reducing the contrast.
Many of the more modern flash units will have a setting for balanced fill in flash lighting, with this setting it is relatively easy to add the flash lighting to the existing ambient light.