B&W conversion is tricky if what you want is a gallery grade image.
Why?
Because careful control of image tone has to be applied and applied selectively to different parts of the image in many cases. Traditional approaches include using multiple layers, where a part of the image has been selected for each layer. You way want to convert sky to darken the sky, while not darkening blue in other parts of the image, and hence the need for a separate layer for the sky. That is pretty normal, and it gets progressively more intricate if you demand fine control over tonal gradations that vary over the image.
Suggestions:
1) Spend the time to learn if you want to attain mastery.
2) Read a good book on the technical aspect of conversion.
3) Read a good book on the artistic aspect of conversion.
4) Pre-visualise in the field, and take notes on what you
want to realise with the image. (Use the B&W mode on
your camera to take a test image to help you "see" in
B&W, but capture candidate images in RAW colour.)
5) Download Silver Efex Pro. You may opt to buy this
software, as it is a great tool which can simply the
workflow for B&W conversion, (but don't rely on it
exclusively for a single pass conversion.)
Ansel Adams spent decades developing and refining his abilities to make great B&W prints. While today's software offers more consistent methods, more control, and takes less time to master than the wet darkroom, be prepared to always be learning and refining. (That is a good thing by the way, it means that you can progressively learn ways to fully realise your artistic vision, that make your style and vision your own.)
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