If you have professional aspirations, then my advice to you is to buckle down and learn/train in the critical foundations of visual art. Right now everything you do looks amateurish because you have no foundation as an artist. You need to learn the basics and then master your understanding of the essential elements of visual art such as composition, values/lighting, shapes/forms, colors, anatomy/figure, etc. Without that knowledge, you cannot be a proficient character concept artist.
I suggest you go to the Art Techniques & Theories subforum (linked below in my signature) and read the sticky threads at the top of that forum, as they contain many very helpful tips on how to learn and train effectively as a visual artist, using strategies that are the most effective, so you don’t waste years of your life running around in circles while using bad habits and methodologies that hinders your artistic development.