Listening on a bunch of different systems and looking for uniformity, such as it can be had. Make note of your room modes, while they are a problem, they can also give perspective. Figure out where your biggest bass is, your weakest bass, etc, and always listen from those spots as well as your sweet spot.
I've got JBL 705P's and Alesis Monitor One's in my studio space, Klipsch La Scala and Advent 2002's at home. Oh, and a pair of different sized Wohler broadcast monitors, really tiny speakers in 1RU and 2RU boxes, meant for broadcast facility signal path cueing and checks. If it sounds right on those, it probably sounds right just about anywhere.