How much of my credit card do I need to have paid to improve my credit score?

When I turned 18 I knew I needed credit cards to grow credit. When I reached the $500 limit on my first card and the $2000 limit on my new card when I found that this was not good for my credit. I hear that as long as you don’t spend more than half of the available balance your credit will be fine. Is this true?

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