Well the best advice is to have a couple of other targets for the ack.. bring friends who will engage the ack at the same time, therefore the ack can't engage all of you.
Otherwise its not easy to take down all the ack alone, you will likely take a hit or 2 no matter what you fly. 190's and other planes with good roll are good for deacking because it gives you the ability to jink really quicky leaving the ack constantly recalculating your flightpath.
One thing guys will do is try to take too many acks down per pass, this usually results in you eating dirt.
Patience!! take out a couple and extend and set up for another pass. Don't let your plane get too fast, hi speed makes you easier to hit. I believe the faster you go the more predictable you are due to reduced maneuverability.
Don't point your nose at any ack for more than a split second
practice.
SKurj