Making Games feel more professional?

I’ve been developing games and I feel very confident in being able to program most mechanics and systems. I also am very confident in my model and rigging skills. While developing games though they tend to feel very sandbox-y and tend to not feel quite as polished as a lot of professionally made games. I’ve added some polish techniques like invisible walls, more linear level design but they still feel “projecty” and not at the level of a product. Any tips and tricks anyone has to make their games feel more professional?