@Doc: You're not being harsh at all! Please don't apologise for this. I appreciate any comment you might have, because I myself are unsure how to improve my images. I understand what you mean with the layer of dull gray. Every conversion I did had some sort of dull gray veil over it. My best conversions are those which were made by an old P&S camera, where scenes were captured in harsh light with big contrasts. And it is exactly Birma and your comment about contrasts and low and high keys which made me think: would that be my problem with B&W conversions?
This picture I took has much more contrast between the cliff, air and sea. Does this mark a better conversion? I do think so, but the level of detail is a lot less than say one of my more gray conversions.
@Birma: thank you for your comments. It got me thinking about my conversions. I know that #1 isn't that special (it's just a banana), but the lighting struck me. If you have anything to add about the above, please do so.
Thank you both for taking the time to help me! It's really appreciated!