See Your InDesign File in a Whole New Light
InDesign offers a few different ways to see how your project might behave on press. The first is the Separations Preview palette, which allows you to turn your CMYK plates (plus spot plates) on and off. This palette also offers an "Ink Limit" feature, which is helpful should you need to see where a file has excess ink coverage (300% being the standard limit).

The Flattener Preview is the other handy palette, if your project has transparency effects on it. I recommend taking a look at your project through the options this palette offers. You can see how the file is handling your transparency effects, whether it's rasterizing vector art, converting type to outlines, or other operations -- the Flattener Preview will show how your project is handling its transparency effects once it goes to rip.

Access these palettes, if you don't have them visible already, under Window -> Output -> Flattener / Separations Preview