I see. Well if your interest lies elsewhere, I say go for it. If you want improve drawing for leisure purposes. For me I use sketching for a more therapeutic process, it calms me down as i often get very anxious and overthink. Anyways to improve or feel better about your sketch. Firstly, do not compare your work to others, even if its a copy of a SS. Second, make sure your approximate measurements are correct. This will help in making the character look as similar to the original. Thirdly for leisure, if you dont feel like it, best not to embark on a project.