I have to admit I'm not a big fan of adjusting your sights on pistols.
It was drilled into me back when I first started serious shooting. I remember an old, grizzled team sergeant catching some young guys adjusting their sights. He stopped them, saying “pistols shoot dead on, always.”
Now we know this isn't totally true. What he meant and I believe is that most shot placement problems have much more to do with the shooter rather the pistol. You have to make sure your grip, trigger squeeze, sight alignment and breathing (yes, breathing) is correct before you start adjusting your sights.
If you are sure you are doing everything properly and still not hitting where you want then you can consider adjusting the sights.
We found a good video from hickok45 that walks you through all this.