Consistent on time payment history and very good use as well as time (unfortunately, sometimes more than a year) will yield a CLI. It takes more than a few months to establish that with any creditor. Follow the advice given and try again in about 6-8 months.
Usage on the CC will be key. An item to keep in mind, although auto-CLIs do happen with BOA, they are infrequent. Your best route is to check with them once you've build enough history. And, if no pre-approved (SP) CLI is available, you'll need to go with HP - which tends to be the outcome in most cases for a CLI with BOA.
But I don't want to take the chance when they're overlooking my history to see if I'm worthy of a CLI and say "Oh gee, why should we give him a CLincrease when his statement reads $0?
No chance to it. It's their account. They know the history. They don't have to rely on reported balances on your credit report.
Ive just asked for a CLI because I spent so much money in so little time, but they said no because my account has only been open for four months.
There you go. That's what you need to work on. Just give it time and manage it responsibly. 6 months is the generic recommendation anyway. Just keep in mind that even usage and time do not guarantee CLI's. If your credit has other issues that don't meet a given creditor's underwriting requirements then you may need to work on those as well.