I'm afraid I'm going to have to give you some critiques if you really want to improve, please don't take it too hard. I can barely even see these light-gray lines over the white paper. A very quick and easy way you can improve right now is to work contrast. It should take nothing more than a quick Levels or Curves adjustment in Photoshop, Photopea or Gimp to make the lines darker (preferably black) so I can actually see what you drew against the white background.
Better yet, find a brush in your software that gives bold, black lines so that even when you're sketching out the image, you can easily see what's going on. Most software has layers, so it's not like you need to draw really faint pencil lines like on actual paper. The way it generally works is that you draw a "Sketch" layer first using any brush you like, then create an "Inking" layer, lower the opacity of the "Sketch" layer, then on the "Inking" layer you basically trace over your own lines from the "Sketch" layer.
I hope you won't hate me for this critique, but the solution to faint drawings like this are very easy once you figure out the workflow, and hopefully by learning to take criticism (even from trolls, they sometimes have a point, but don't express it in a delicate way), it would only be a matter of time before someone decides you're good enough for the Art Portal!