6.

Once you reached your desired number of Smart Object layers, you'll see that the combined image looks very flat. You can now start adjusting the levels on each individual layer. Go to the Layer menu, drop down to Rasterize and choose All Layers. This changes the layers from Smart Object layers to normal layers.

Adjusting the levels on each individual layer is maybe the step that requires the most attention and experimentation. The general idea is to increase the dynamic range for each layer seperately, eg. by darkening the midtones and shadows on the bottom layer(s), and by lightening the darkest tones on the top layer(s). Experimenting is the best option here.

A bit of finetuning and that's it...

 

This may all seem quite complicated, but once you get the hang of it, it shouldn't take more than ten or fifteen minutes to complete the whole procedure.

Hope this has been useful... ;o))

We do not see things as they are. ǝɹɐ ǝʍ sɐ sƃuıɥʇ ǝǝs ǝʍ