Well, I usually start by panning things out and getting a good stereo spread. Then I start listening for eq crowding (too many parts in the same freq. band) I try cutting to create holes for each instrument and the vocals. Then I sleep on it.
Next day I go back over the eq, and add effects. Cut a rough tape or cd and play it on my boombox, in the car and on as many home stereos as will still let me in their homes. NOTE: Don't adjust the tone or volume from the last thing they were listening to and see how it sounds. Keep notes and when you're heard that one enough times, go make the final adjustements and repeat the preview process.