Photography and Photoshop Feedback

I don't like to point my camera lens directly at the sun.  It rarely produces good results and it can destroy your camera sensor.

Owing to my experience with film cameras, I think of double-exposures as unintended glitches. Sorry.  Nowadays, double-exposures are a special effect. As with any special effect, it can work in some but not all situations.  Also there is a fine line between art and gimmicks.  You should avoid the latter.

Adobe Stock has 1.4 million examples of double-exposures. Compare yours with what's available. Ask yourself if you would buy yours and what you would use it for?  Good Stock photos should convey a mood or message. 

https://stock.adobe.com/search?k=%22double+exposure%22

Hope that helps.

The first: 

Noise and colour noise (half circle, but basically everywhere), a blue point reflection (from the lens),  and a main subject that is not clearly defined.

As for your artwork: Adobe stock is not the correct place to sell that. You will need to publish the correctly edited source files and let the buyer do the layering. That's not a lot of work for someone knowing how to handle Photoshop. And that would allow the buyer to use their effects in the strength as needed.

The first photo also has a blue spot in the water that should be removed. Also, the ID on the sail must be removed.

The first image is quite noisy and there is a large blown out area. The second image also has noise. The third image might have been rejected due to overexposure.  There is banding in the sky in the 4th image.