How exactly does a credit card work?

Question

If I get a card with a $300 credit line and use around $200 for purchase how would this affect my credit score?.

The smart way to build your credit score is to use 50% of your credit line. Some of the best practices to raise your credit limit is to pay off your balance for that month or pay half the amount and the other half the next. Paying the minimum due may get you into trouble and would results to increase in your interest rate. However, if you cannot afford to do so then pay the minimum amount due just make sure though to make another payment for that month which is twice the minimum. This will renew the cc company’s trust in you and can confidently call them for a lower interest and a higher limit in 6 months.