Maybe, only real weakness that I have found is a HO. Is their a trick because I haven't found one.
The HO ain't that good, because it leaves you little time to aim&fire, puts you in a bad position to set up follow up attacks and a good gunner might get you because you are coming straight at him.
Overhead frontal quarter attacks are one of those that can work quite well, especially if you have a cannon equipped plane. This is the one most difficult to counter for enemy gunners, the rapidly changing angles and high speed of closure makes you a most challenging target. Give enough lead when aiming and let the bomber fly through your stream of shells. Depending on tactical situation, a lower frontal quarter attack may work as well, or even better (for example when you are in a jet vs B-29s, the devastating upper front turret with its 4x.50 can be avoided by this)
A proper set up is very important, most fighters die to a astonishing lack of patience - they may stalk a bomber for 15 minutes but refuse to invest another three for the final setup, flying up to the bombers six instead. Get to speed, get into position. Before attacking, already think about egress and set up of your follow up attacks.
And best fly a lot of bomber sorties yourself.