For me the key to finding good award availability is flexibility. I maintain balances in AA, US, UA and DL because I never know which will has the best availability for my particular trip. Next month's trip is with US miles, my last trip was with UA miles, my previous two trips were with AA miles. I even made a good redemption with DL miles in 2011.
And I never book anything more than 2 months in advance, because my life is too fluid and changeable. Obviously everyone's situation is different, but having flexibility is almost always a good thing.