Teach me how to merge photos

[Astrogeezer]

I posted here previously, asking a similar question.  I need someone to show me how to merge these photos.  My workflow currently is:

1.  Use the selection brush tool and the flood select tool to select the area that I want to keep in the final image

2.  Mask that area

3.  Place the photo I want to merge with that masked area

My problem is selecting that area.  When I work with complex areas that have intricate details, my workflow produces lousy and frustrating results.  Can someone show me how to do steps 1 & 2? Or provide a different workflow entirely?  I'm not a power user or even a terribly competent one.  Please be detailed and patient.

Here are two files I would like to merge.

Thanks in advance.

 

 

 

[prophet]

I'm always a fan of using an image as it's own Mask if possible.

Here's my rough take…
• Dupe the top layer and Rasterize
• Apply various filters to get a high contrast Black and White proto-mask (used Exposure and Black & White and merged as I went)
• Clean up
• Invert
• Clean up again (you could spend a lot of time cleaning and retouching depending on how precise you need the Mask to be)
• Rasterize to Mask and nest into top layer

 

[thomaso]

Just roughly masked with Flood Select on the dark areas + Brush.
For the water reflection in blend mode Lighten: a sky copy (flipped, moved, stretched) with a separate mask.

[prophet]

Ooh, I forgot about the reflection in the water. Good catch @thomaso

[Astrogeezer]

Thanks.  Let me give it a shot.  I also just noticed that it's easier to rasterize when there are no layers in the file.