#1 - Your subjects are out of focus and the tonal range of the image makes the B&W conversion rather bland. This needs a lot more contrast. The highlights on the door are distracting.
#2 - Not a good use of selective color. The face is hidden in the shadows and could have benefited from fill (reflector, etc).
#3 - This looks like a family snapshot, reinforced by things like the blown hots pots on faces. Focus seems to be on the tree behind the people?
#4 - This is a picture of a chair. It lacks anything interesting. The composition is nearly completely centered, there's not a whole lot of contrast, the lighting is not remarkable. There's no real 'wow' factor in the image at all.
You've got a lot of room for improvement. Keep at it, esp with that many models at your disposal.