Bike shot ... not sure what you were trying to show there, but its not that interesting.
The flower is better ... you need to work on the tonality, as it looks flat.
First guitar shot looks like a test of depth of field.
Second one has a theme. Needs working on composition and lighting ... keep working on getting that one better.
The Sharpie reminds me of your first guitar shot.
I think the tree with path would be more interesting in wider angle.
You need to work on your B&W ... like many others, they have no B&W in them, too much mud.