it'll be good if you've shot from the other side of the subjects where we can see the face.
Subject dead centre. Remember rule of thirds. However, good choice of subject cos the rose looks good/attractive as a subject. Could also try shooting closer (ext tubes or macro lens will help here) to help create more background blur.
I see your idea, but there's no subject to draw the eye into the picture. The 'subject' that I can guess from your picture is not even in bloom. So, do take care of where do you want your viewer's eyes to dwell on.
safe landcape. Try to include humans or subjects into your picture to show proportion, such as houses or animals. Also makes the picture more interesting.
Another idea is to include some foreground. You're using a telephoto which compresses the hills and the sky. Using a wider angle (or maybe you've cropped your original picture) helps to create depth for the 3D effect in a 2D film.
I'm commenting on the the pics, as I would of my own.
#1 woof, doesn't tell much. For me I would try to capture the image
from the woofer's perspective or height. Probably a glimpse of their
reaction or maybe at their height.
#2 Well just ask yourself what're you trying to achieve here? Do you
want to portray the crispness of the petals, beauty of the rose, etc.
For me I'd choose a different angle, perhaps top down, or downright straight, or something! get the creativity cracking! Sprinkle some water to the petals adds appeal. Nothing wrong with your macro and lens though.
#3 I love shots like these! However take note of the off focused flower on the right. Kills the photo. I'd choose a different angle too though, maybe lower or higher and include some of the background by turning up your settings.
#4 lacks sharpness and beauty.
Its not about how many people comment on a few pictures, but rather you should just continue to shoot and learn from your strengths and weakness. Later, go and challenge yourself with new concepts. For eg, when I go for photo clinics, I may only have 1 or 2 views from a single coach, but he takes time to tell me how to improve and it is good enough than have too many different people making comments. Do remember different people have diff taste and styles.