For future reference, if you only got 30k miles from an AA card, you should have waited for the 50k bonus that comes around every so often (unless you had some immediate travel plans).
I usually wait till around month 10 or 11 before calling to try to get a retention bonus (allegedly banks don't like it if you cancel right away and may not approve you for new cards from then. How true is this? I'm not sure. But it doesn't cost you anything to hang onto the card until month 10 or 11). If they offer to waive the annual fee, great! I keep it for another year. If they offer some miles/points for $X in spend, I give it some thought. Depending on the offer, I might cancel.
Before you cancel any card, make sure you don't have any pending rewards that you want to hang on to. For cobranded airline cards like the AA card, so long as the miles are posted in the AA FF miles account, you're golden. For cards like the Chase Sapphire Preferred, where the points are issued and administered by Chase, transfer or use your points before closing the card.