A comment to Fran, based on the quoted sentence of Rich's:

For those of us undertaking new processing, or new subjects (such as first-time still life or studio portraiture), or really any photography related tasks, sometimes we can't pinpoint what we aren't happy with. In that case, it can be hugely valuable to have the input of others.

When considering the advice or observations of others, if you aren't familiar with a user's work, just click on their user name and view some of their topics. This will help you determine whether their style, skill level and interests can translate to something of value for you.

Lastly, regarding ideas for conversion to b&w, you could share a high-resolution color shot (un-edited), or use free dropbox to place a raw file, so that others can edit. Best section to do this is probably Post Processing.

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When changing over from colour to B&W, one of the differences that you need to come to terms with is that B&W frequently (but not always) needs more contrast. However, when you use the Contrast slider, one of the things you have to watch for is the dark areas becoming too solid and impenetrable and/or too large. That can be countered up to a point with the Blacks and Shadows sliders. You may also find that the bright areas become too harsh and the highlights can get pushed into saturation (i.e. blown highlights). The Whites and Highlights sliders can alleviate that (up to a point).

The haloing around the tree line in the sky suggests that you're already using quite a lot of Clarity (or possibly that the image is an HDR merge, or it has a Picture Control profile baked in - which is often the case with SOOC jpegs). The best approach is to make Contrast adjustments as described above and make that the main way to add contrast. The Clarity slider should be left to the end for minor tweaking.

Another possibility is to add contrast via selections and avoid including the problem areas as described above. Alternatively you could add the correcting adjustments via selections. In your picture the area inside the shed is already plenty dark and you could select that area to lift the shadows a little. You could also select any problem bright areas and give them their own corrective adjustments for similar reasons. That frees you to add more overall contrast to the rest of the image.

It's very often the case that global adjustments can be pushed further if you can mitigate the unwanted effects that the pushing produces. That way you can get more of what you do want and less of what you don't want. There's more than one way to apply corrective adjustments, some of which are described above.