Here are the two most common adjustments you can make—ones from which any print job can benefit.
Adjust “cropping.” A photo’s proportions rarely match the proportions of the paper size you’re using. I don’t know of any digital camera whose photos perfectly fit an 8.5- by 11-inch sheet.
With some programs, mismatched proportions yield prints with uneven borders. iPhoto eliminates that problem by enlarging an image until it fits the dimensions of the print size you chose. That gives you nice, even borders (or a fully borderless print), but at a price: parts of the photo’s edges are cut off. In this example, iPhoto cut off part of Sophie’s ear (ouch).
By positioning a photo within the print area, you can control how the photo ...