Try not to focus so much on not being able to draw as well as the professionals who made the shows you're copying from. Instead try to frame things positively, celebrating each new thing you can do.
Most animated shows have specific rules about how to construct characters, so see if you can find a "model sheet" for series you like and try to learn the rules so you can construct new poses from scratch in that style!
It's also a good idea to start practicing at drawing "primitive shapes" like cubes, cylinders, spheres and the like, because most cartoon styles construct characters using these to give the illusion of depth. Here's a model sheet of Homer Simpson where you can see how the animators construct him out of tubes and spheres creating a 3D-like cartoon body. You can teach yourself to do this with a little practice and you'll soon be making things that you feel pretty proud of!
First thing is get used to drawing softly in pencil to construct your characters in a way where it's easy to gently rub out unwanted lines, or working on a sketch layer digitally.
And my final piece of advice: Not every drawing you do will be presentation quality. That's normal and is the case for literally everyone. Most artists do practice sketches and a lot of them just don't show anyone. It's perfectly fine to have a bunch of crappy drawings for every good one. Just keep at it!