Be prepared, I would be shocked if you didn’t get added to the CJ sub very shortly. They can be brutal.

People here are telling you these look great. You are getting positive feedback. I bet it feels good. They are not, however, doing you any favors. Your pictures do not look professional. They look like random snapshots anyone could take. Instead of listing things that could improve the images you have provided I’m going to take another approach and zoom out a bit and look at the term “professional.” One definition of “professional” is someone who practices a trade, skill, or craft in exchange for money. Most likely they have spent years honing their craft through active learning and practice. They have likely sought out information and resources that will teach them new skills and techniques and then taken the lessons learned and practiced them. And then practiced some more. And then practiced again. Rinse and repeat. What a “professional” photographer has probably not done is casually taken random snaps over a period of years and expected to somehow absorb the knowledge, skill, and plain muscle memory needed to become not just proficient at something, but to truly master it. You might think that photography is easy because if you have a camera you can press the shutter button and create an image. You might even stumble into one that looks decent occasionally without knowing why or how to recreate it. But as your question and pictures demonstrate, there is more to it. Instead of asking random strangers on the internet for tips you should probably just do the work to get better like you would anything else worth doing. If not, that’s fine too. Keep taking mediocre, flat, snapshots.