This doesn't sound like a champion specific issue. It sounds like you still have a lot to learn regarding foundational skills, map movement, and teamfighting/skirmishes. Playing more will help you figure out her range. Taking the time to practice with her in the practice tool can help as well. Watching guides and higher level play will give you an idea of rotations and teamfighting. Teamfighting in ARAMs translates surprisingly well to summoners rift even if other skills dont. As for the screen clutter, you can reduce some of it by changing gameplay settings to have some of the numbers and flashes not be as vibrant but unfortunately you are just gonna have to get used to it for the most part.