Well you didn't say 6 bolt or single pivots but this will work:
Pop off the back cover and tighten the screw nearest the neck joint to increase your spring tension. The trick is to replace one string at a time but it's likely too late for that so here's what you do next: tune the D a bit sharp, then get the G close but flat, then the B, then the A, and go back to the D, the G, the B, the A and the high E (1st) save the low E for last. Now work your way from the center out until you are close. Check the spring tension again and tighten if need be. Tune to pitch from the center out. Stretch, retune, one more check on the springs, tune.
I've seen a lot of string stretching techniques, here's one that works: place the string so your 8 fingers are on one side and two thumbs are opposing, somewhere near the 12th fret. Pinch. Do not pull the string up, you'll just end up filing the nut and tweaking the wang bar. A good pinch will drop the tuning 1/2 step and much more nearly replicates pressing the string down between the frets.
I've put somewhere around 100,000 guitar strings on using this method and it works well for me, should work for you.
