How To Make Fog With Photoshop?
--- If you wonder how to add mist and fog effect to photos, here are some quick solutions.
--- First you have to prepare the photo. Decrease the saturation, lower the contrast and maybe add a blur to create a foggy effect.
--- You can add a white Color Fill adjustment with 5% opacity level.

To create fog effect in Photoshop you can try these methods:

--- Fog Photoshop brushes – pick a white or light gray color and simply add fog using fog Photoshop brushes.
--- Fog Overlay 1 2 – add the fog overlay over your photo and set the blend mode to Screen.
--- Clouds Filter – create the fog texture overlay using the Clouds Photoshop filter. Use black and white for the foreground and background colors.
--- Fog Photoshop Action – use this action to create the fog and mist effect

How To Use The Fog Effect Photoshop Action?

--- To use the fog Photoshop action you have to follow these steps:
    --- Load the ATN file in Photoshop.
    --- Play the "Fog Photoshop Action"
    --- Customize the fog effect using the Brush Tool

--- This action creates fog&mist, but you can also use it to make smoke effect and even fluffy clouds.
--- Use the Layer Mask and a soft round brush to customize the result.