@damsonwhufndthis I was playing some matches with a Predator last night and we were talking about strafing in general. It sort of depends on the gun you're using and the legend.
An Octane stim strafing is nearly impossible to hit with a gun like the wingman.
As others here have suggested it really boils down to practice. Depending on how close you are, hip firing can do the trick. But for the hip firing to work you have to be fairly close to them.
One thing that can help is sticking semi close to your team. If your teammate is shooting at the enemy from the side their strafing won't do much for them.
If you're really struggling with it, slower firing weapons can help. Something like the Flatline, it has a large magazine and slow fire rate but still packs a decent punch. So if you miss some shots with it, you'll have plenty to hit the enemy with.