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Basically what other people have said in this thread already.
1. Draw a lot of character designs. You'll expand your library and now where to go with designs.
2. Use references, use a lot of references. Don't take inspiration from only one reference, take from multiple. Use references that work with what you want to create. Don't steal entire designs.
3. If you don't like a design, remake it. I've remade the design of almost every character I am making for my story, even if just little things. Usually designs don't look the most polished or clear the first time.