This is the easiest of the vehicle-based missions to complete undefeated in my opinion. It's not too hard.
Use the Tie Interceptor. It's fast and maneuverable, has good firepower, and is smaller than something like the X-wing, making for a smaller target (i.e you won't get hit as much).
Concentrate on nothing but completing the level. Don't be distracted by canisters or Tie gates.
Keep an eye on your health and try to keep it topped up. Keep your eyes peeled for hearts lying around from downed enemies etc. Destroying the blue panels on the walls is useful as they very often yield hearts too.
Gun emplacements are a much greater threat than enemy fighters, but they have a limited range and can be taken out from middle distance without being hit. Don't stay still while shooting them though or you'll be a sitting duck for enemy fighters.
Destroy enemy fighters when you have the opportunity, only because you don't want to have 4 or 5 attacking you at once. Don't get involved in lengthy dogfights though if you can move on to the next section and leave them behind.
In the final section, through the trench, the above tip about gun emplacements is particularly important as they are very numerous and are the main threat. Take them out one by one before they can shoot you. This is pretty easy. Just don't get too close to them. Keep looping back every time you get close to their range. When doing this, also take the opportunity to shoot Vader's wingmen that are chasing you. You'll be able to get rid of both of them by the time you're halfway down the trench, but don't make any special effort to kill them, they don't pose much of a threat. Don't worry about Vader either - you cannot hurt him and he gets dealt with automatically anyway. Keep an eye out for hearts on the ground if you need them.
At the end of the trench there are three groups of four gun emplacements. Deal with each group on at a time. Fly over to make them appear, retreating before they can shoot you. Take them out from beyond their range. Repeat this for all three groups of guns. When you have done this, the final target appears. Hit it with a pink orb to complete the level.