Sometimes the best way to spice up a photo is to make it look faded, and digiKam makes it supremely easy to achieve this effect.
Open the photo for editing and choose Color → White Balance. Adjust exposure compensation to slightly overexpose the photo and set the color temperature to 12000 to add a strong golden tint to the photo. Press OK to apply the modifications. Choose then Color → Hues/Saturation/Lightness and set Saturation to -50. Press OK, and you are done. The described technique works particularly well with skin tones, so it’s suitable for use with portrait photos.