ASiegel,
My following comments are under the assumption you already know your gear, how to properly expose an image, various focus, metering, and stabilization modes, etc. In your post you mentioned you have taken a big jump the past 2 years which is tremendous news. Therefore, I'm assuming the basics are already well understood.
Past the basics, there is more nuance and subtly to hitting the next plateau. I think most of us have been there or are currently walking right alongside of you as we go through our own journey.
As others have said is study images you like and try to understand what it is about them you like, is it the subject, the colors, the lack of colors, the placement of the subject (composition), all of the above, something entirely different. Did the image make you feel a certain way? Did you feel empathy, compassion, love, anger, discomfort / uneasiness, joy, happiness (they are different by the way), contentment, something else? What about the image made you feel that way? Try to isolate what elements of the image elicited that emotion in you. Regardless of the feeling, identify the elements that created that feeling and then decide how, when, or if, you could use those elements in a photograph. Personally, I spent enough of my life in a super stressful job and many times I was paid to be confrontational. I don't enjoy images that bring me back to those dark places in my mind. I like images that make me smile, feel happy or joyful. Images that elicit a feeling of hope and better days ahead are the ones that attract me and what I try to broadcast with my photography. I've seen enough bad (evil) I want to see more joyful and good. Some will think I'm naive and suffering from wishful thinking. I'm far from naive (in fact, I can be quite cynical and have seen a lot and heard just about every type of lie that can be told). Wishful thinking? Maybe, I want to see the world be a better place than it is today. I want my photography to tell a story about nature that will give people a reason to desire to get closer to the natural world and, hopefully, take steps to help preserve and protect. These are the emotions I want my photography to elicit.
A good image should stir some emotion otherwise it is probably just a well exposed, in focus snapshot. Nothing wrong with snapshots, I have hundreds of them in my library, but those are not the images that people will remember long after seeing them. The photographs that make us feel something are the ones we remember.
Not that you want to copy someone else's style or image but with a good understanding of what you find pleasing then you are better prepared to go out and capture images that please you.
Another thing, very few of us here are making a living at nature photography. A few are but most of us would be hungry photographers if we tried to make a living at it. That''s cool, fact is, it gives us freedom to capture images that please us and make us happy without having to worry if someone else will enjoy it enough to give me money for it.
Now, what has been the single tool that helped me to reach the next plateau once I became reasonably proficient with the technical aspects of the process? Don't laugh, the DELETE key. Become hyper critical of your images. I'm not talking photos of the family, friends, vacation memories, special moments. I'm talking about your everyday photos. Look at them with a critical eye. Think if you saw someone else post that same image would you say "wow" or would you ask "why did the bother posting that one?" If / when one (ok dozens) of my photos fall in the latter category, I delete them. I no longer want to look at them, they are doing nothing to help me improve or to stir some emotion in the viewer. They do not tell a story (or a compelling story) and they will not be effective in helping me to build interest in the beauty of everyday nature that surrounds us. Images that fail to do these things get sent to the recycle bin. I am heartless in my use of the delete key. Unless the photo is of something really rare, a very unusual behavior, a subject that I just so beautiful that I must do whatever I can to salvage the image, I do little to no post processing before I hit the delete key. I don't want to waste my time salvaging an image that I will not use anyway.
Be your own worst critic. Don't be artificially hard on yourself, but also do not delude yourself into believing every image is a masterpiece and someday will be published placing you among History's greatest photographers. Maybe you will be and I sincerely hope you are. Nothing would be cooler than to see someone on this forum get that kind of recognition. Even so, I would assume even those masters delete more than they keep.
So, that's my long winded extra lengthy babbled on too long answer.
Hope it helps and that you and all here have a wonderful day.
Jeff