Sketching Manga...what Am I Doing Wrong?

I'm a beginner at drawing manga like drawing characters and I'm pretty ok for a beginner maybe even really good but there are some things I dont know if I'm doing it right... I tend to erase alot, and press hard on the pencil, and when I draw lightly (well not really) well I guess what I'm trying to say is... What is the drawing-inking process? What pencil to use? Sorry if I confused u guys I just lost my

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