Hi, Silke here.

First create the smoke effect:

Create a new document in Photoshop 3600px x 3600px with black background. Create a new layer. Set foreground color to white
Pick a soft round brush, hardness =0. Size 300 pixels. Opacity 100%, flow 40.
Brush a “S” curve through the page from top to bottom. Stay on the same layer.

Go back to the top of the page. Reduce the size of this brush to 150 pixels and brush in another curve that loosely overlaps the first one.  

Go to Filter>Blur > Gaussian blur> 65 pixels.

Now go to Filter > Other > Maximum> Radius 36.6 pixels – preserve Roundness.

Hide the black background and save your smoke as a transparent PNG file.
Save and close the Photoshop document.

Apply the smoke effect to a picture:

Take or choose a picture of a coffee (or tea) cup. Open this picture in Photoshop. Open or Drag the Smoke file (PNG) into Photoshop. Add it above your picture. Use the resize tool.
The result depends on the background of your photo and also on the intensity of the smoke you intend to reach. You can duplicate it once or twice if you want it to be more visible.

I did a layout using this image from Pixabay, then added the smoke on top of everything, giving a certain realism to my page. See it here below:

Layout created with my MULLED kit and collection that is 30% off until January 19th.

Link to my store: here
And here I did a little free sample for you, in order to test the Smoke effect!

Download it here