Gettin' Round Those Corners

Since the dawn of time, or, at least since Star Wars premiered one thing has bugged many, and that's those darned ships and the way they move. To whit there's all this 'conservation of momentum' stuff that just has to be addressed. Things in zero gravity don't really execute tight curves. Things in space go where you pushed 'em, and you have to stop 'em before they go somewhere else. There have been lots of models of why these darned ships do what they do.
The silliest is the 'Aether' theory. That theory suggests that space in the Star Wars universe isn't a vacuum after all and that there are 'aetheric' molecules in space and they work as a drag element. This is of course bum-biscuitry of the first order.
The next most common is the classic model whereby ships have thrusters (tiny invisible ones) thrust vectoring and all that jazz that can execute sufficient thrust (invisibly) to pretty much stop a fighter in fractions of a second, and then propel it in other directions just as quickly. I could just about buy that for, say, the battle of Yavin, but I just watched the Battle of Endor and four fighters make a ninety degree turn at flank speed without raising a sweat. I'm sorry folks, but this model just doesn't cut it. In addition to the implausibility of the thrusters being able to operate that quickly every Star Wars ship has BIG engines that face in only one direction. Now you can use these with thrusters to make an effective fighter, but it'd move like a Viper in BSG03. (Vipers in Galactica are awesomely cool, but it's a different universe).
To me these just don't cut the proverbial mustard. There must be something else. My solution to this phenomena also happens to explain one other annoyance, the TIE fighter wing. Now I'm only going to use a technology that already exists, repulsors. There are two repulsor systems in play here.

Drag Simulation

Star Fighters already have inertial dampening fields, this is just an extension of the same gizmo. A field creates an artificial drag field on the ship itself with a certain degree of retarded motion allowing the vessel to thrust against this field providing the neccesary counter force to turn the ship. In addition to this the drag simulator allows the ship to coast to a stop, which could be handy. The DSRs however certainly wouldn't provide enough of a force to really explain the extreme manouervers made by combat starfighters, for that we need another system.

Gripper Repulsors

We know ships have tractor beams, we've seen 'em. My allegation is that most fighters feature essentially wide band tractor beams that lock onto nearby objects to provide an anchor around which the fighter can swing. Now, these tractors are generally found in the 'wing' sections. Notably the TIE fighter has HUGE gripper emitters.

X-Wings have four grips, B-Wings three, and the rest are fairly obvious too. These work according to a navigation computer's whims and best when in close proximity to large objects or vessels.As a side benefit of this system most ships would have, during dogfights, several tractor beams locked on to each other with varying degrees of power and that means there's suddenly a mechanism by which it is possible to hear ships in space, and THAT is kick ass. Even blaster shots can be heard to a degree because the shots are audible inside the ship, and transmitted through the beam.

TIE Fighters have two big arrays and this gives them exceptional manouverability but could cause problems in tight spaces since their giant fields emit mainly sideways. Consequently minor piloting movements can translate into severe lateral; movements, which would be catastrophic if you were, for example, in a small trench or crevice on an asteroid.

Under this model manouvering charcateristics would be a combination of thrusters (still the easiest way to rotate a ship) thrust vectoring including vectoring by Drag Simulators, the speed and reliability of the navicomp and the capacity of the grippers.

There are some fighters that don't really feature wings, the A-Wing and Aethersprite in particular. I'd label both of these ships as interceptors, designed to get somewhere in one hell of a hurry, and engage low agility targets with lethal force. Manouvering isn't all that important for this role, and these ship' grippers are intergrated into the spaceframe. I'd like to remind readers that the Aethersprites seen in the movies are pilotted by Jedi and their abilities can account for a lot of dramatic moves.
Larger ships lack wings too, and I'd argue that their ability to turn is dependant on high power 'gun type' emitters rather than more efficient 'array type' ones.