When I crop a picture, I want to keep it in a ratio so I can print it later, and have it fit the picture as it would straight out of the camera. Know what I mean? Like after I'm done cropping, it's a rectangle, or square, or whatever, but I want it to be the perfect shape of a picture. Can that be done in PS?
You can select whatever crop size you want. Do you mostly print 4x6? Make sure you crop to a ratio of 1.5:1, etc. I use a standard crop of 10x15 (which is 1.5:1, BTW) for the reason that this has the most compatible print sizes at DPCPrints.
But how do you do that? In PS when I hit the crop tool, it just lets me do it freehand and there is no place to type in any commands
When you choose the crop tool you have an option in the top bar called "Style". The default is "normal" which allows you to do it freestyle but if you change that to "Fixed Aspect Ratio" and plug in strangeghost's ratio of 1.5 x 1 in the width and height boxes you'll get the crop you are after when you start using the tool.
In older versions of PS, crop doesn't have a handy menu (that I've ever seen), so I use the rectangular marquee, set the options to Constrained Aspect Ratio (one of the tabs by the Navigation tool box) and dump in my numbers (1/1.25 for 8x10s, 1/1.5 for 8x12 - there's a good list in Sellers Tips at DPC Prints), select my photo area, new layer via cut, discard the background, and then crop to the size of the visible photo.