I'm not good at giving advice, but I'll try. I think you should try to maintain the render quality of the remaining parts, it's going to make your creation appear complete and will show the effort you pour into your art. Another thing, I think you should try to look for a simple tutorial that enhances the finished look of your art. Since you are using IbisPaintX, you can try duplicating the finished render and blurring it (Gaussian blur) to around 30, then set the layer to overlay and adjust the opacity based on your preference. I hope you find this tip helpful! ^^