Diffused, soft light is the type of light you find in the shade, on a bright but overcast day, or when there is fog or mist in the atmosphere. The lack of directional light means there are no shadows and therefore you will not get the same sense of shape and texture that you would with a strong sidelight. The image becomes flatter and has less contrast.
While these may sound like many disadvantages, soft light has many advantages. For example, it is often easier to expose correctly in soft light situations since the available light will hit your subject evenly. You will not have the complication of distracting bright spots.
Lack of directional light means there are no shadows. You will not get the same sense of shape and texture.
Soft light is also excellent for colour saturation. When you are faced with soft light look for contrast in colour. Some of the best soft light photos are those that include colours that are opposites on the colour wheel.
But what about that bright white sky? The best and easiest option is to exclude it from the frame. Use the opportunity to focus in on the details. Tighten up your composition and take close-up photos of foliage, wildflowers or details in architecture.
Another option on an overcast day is to photograph waterfalls and streams. You will be able to see more detail in the water under diffused light. Also, the low light will allow you to use a longer shutter speed which will blur the motion of the water and give a silky smooth effect.
Soft light also works well for taking outdoor portraits since shadows and textures on skin are not flattering, and neither are squinting eyes. Your subjects will thank you for making them look younger in soft light.
Because of the low contrast found in soft light scenes, be sure to add contrast to your image in post-processing.