4cb68544__Capital_One___Credit_Line_FAQ__If_your_letter_says_
[What that means] In general, customers who are most often approved for credit line increases tend to use more of their credit line, either by spending and paying off the card each month or by keeping a balance on the account and paying it over a period of time. [What you can do] If you plan to use your card more, make sure you use your card responsibly. Add AutoPay and customized alerts to help you make more than your minimum payment on time each month. You can also use Capital One® Credit Tracker to help monitor your credit score. [If your letter says:] 
Recent usage of this account's existing credit line has been too low.
Credit Line Increase FAQ | Capital One - Credit Line FAQ
If your letter says: