When and how you pay is the single most important of your credit. According to FICO, past long-term behavior is used to forecast future long-term behavior.
Those who are always maxing out credit cards, or who get very close to their credit limits, are viewed as irresponsible and will pay for it.
The longer your credit history, the more information for creditors and offers a better picture of long-term financial behavior.
Avoid opening too many new credit lines. Practicing such behavior could suggest that you’re having problems financially and are in need of credit.
Having diversified sources of credit shows that you can handle all sorts of credit, which represents less risk for lenders.