Wing Commander IV
The Origin Cluebook is pretty good.
You ought to do the following things ... (in my opinion).
Practice sending off salvos of torps.
For the "impossible" mission early on, all you need is a single torp salvo to kill the carrier.
You launch, assign one of your wingmen to attack the one enemy wing, then assign your other wingman to attack the other wing (use the dialog buttons on the communicator -- otherwise when you have more than one wingman the altB and altA, etc. keys don't work right). That will tie up the escort and you make a single run on the cap ship, killing it with a torp salvo. It becomes easy instead of a killer.
Save the "superweapon" as long as possible (i.e. bypass the star base instead of killing it with the flashpack).
Remember you can turn invisible, fly inside of enemy ships and drop off flashpacks, flying out ahead of the explosion.