One good idea is to keep an eye out for the enemy's warp-in point. Subsequent wings of fighters and bombers have the same warp-in point as the previous wing, so if you can station yourself or a wingman in that general area, you'll have a better opportunity to start hitting them when they warp in, and be able to smack them all the way to their target.
If things have really degenerated to the point where you and your wingmen are just fighting for your lives, try just ordering an all out attack (C-3-9) and everybody will just start shooting at anything. A full-on furball is rarely the best defense, but the enemy's attack will be at least as confused as your own defense.