Tips I got from Bas & Hyperpro.....
Tighten the pinch bolts on the nut side fork tube first. Then vigorously depress the front suspension a few times (with front brake applied obviously) before tightening the pinch bolts on the opposite side. This allows the fork/axles to 'settle'!
Also, make sure that the holes in the axle (other side from the nut) are such that they are parallel with the ground when you have finished torquing the axle nut so that air can pass straight through. Easy enough to do using an Allen key or small screwdriver. This prevents some whistling noise. Never heard it myself but I do what I'm told by people who should know.