Your credit score affects loan approvals and interest rates, which can cost or save you a lot over time. The good news: the levers are known and mostly in your control. Educational only.
Payment history is the biggest factor. A single missed payment can hurt for a long time, so automate at least the minimums. On-time payments are the foundation of a good score.
Utilization — how much of your available credit you're using — is a major factor. Using a small share of your limits looks far better than being maxed out. Paying balances down (and not just on the due date) helps.
Length of credit history helps, so keep old accounts open and in good standing rather than closing them. A longer average account age gently lifts your score.
Each application can cause a small temporary dip, and lots of new accounts at once looks risky. Apply only when you need to.
Mistakes on credit reports are common and can drag your score down. Review your reports and dispute genuine errors — see getting out of debt for tackling balances that hurt utilization.