On my way to my local indoor shooting range yesterday, I stopped at a gunsmith shop I hadn't visited before. It was just a visit to get to know the personnel and where the shop was located. The owner happened to be out, but someone working in the shop was very helpful. My rear sight was not centered in the dovetail. It came to me that way. I don't know if the sight shifted in transit, or came from the factory that way. The plastic box was cracked, and piece of it were missing. I was so excited when it arrived at my FFL, I didn't notice this. The target that came with the pistol showed that the hit spot was left and low of the aim spot. Looking at the rear sight, you could see that it was off set to the left, looking from the top down on the hammer, muzzle pointing away from you. One of the smith's there tapped the sight more to the center of the dovetail. Before you could feel the edge of the sight sticking over the left side of the dovetail.
This smith told me about a website that has targets you can print out to help you correct aiming problems you might have. These are free targets you can print out and take to your local range. (There are several such websites, but this one is easy to use.)
http://www.persecusa.com/html/free/freestuff-targets.htm#DIAGScroll down about halfway and you'll find the targets for diagnosing common shooting errors for right and left hand shooters. I wish I had some of the targets to take with me to the range. I noticed when I got home that I have multiple problems. The major one is the lack of consistency. It just means I need more range time. And patience to get repeatability in my shooting. I hope these will be useful to you at the range.