After associating run aireplay-ng -3 -e <essid> <interface>
Then run aireplay-ng -0 20 -e <essid> <interface>
You may want to try -2 and -4 too. Just try em all, and hopefully it'll click in somewhere. At least that's what I do, and it's been working a charm.
EDIT: I misunderstood. If you didn't get association you may need to move closer to the AP or maybe MAC filteringis on. Try to find an associated MAC and use macchanger to make your MAC identical.