One other thing to keep in mind is the aspect ratio of the paper is rarely the same as the picture. That is - (for example) - the long side of the picture may be much longer than the short side, when the long side of the paper is only a bit longer than the short side.
More specifically.... an 8x10 piece of paper is nearly square, however most DSLRs shot something that is longer and narrower. If you want to fill the paper fully you need to crop the image to the same aspect ratio of the paper. If you want to print the full image you will end up leaving white (unprinted paper).
Also know that it is very easy to print a large digital picture to a smaller piece of paper....but your results will start looking soft and mushy if you are trying to print a small picture to a bigger piece of paper.
jbg232 is right about getting accurate prints..... however, the printers are usually not the major problem it is the monitor. Get that right and, unless you're unlucky, the prints will be pretty close. To get them better then you will need to explore the world of paper/printer profiles.
And you thought photography was easy, eh?