Answering a question at TOMB, I said:
I hate sub-woofers, also, unless I’m lookin’ to hype a movie or rock music for pleasure listening.
That said, in accord with the above, pick a spot, any spot, but the same spot, sit there and listen, at the same levels (buy a SPL meter if necessary – great tool), to stuff you love, hate, and have done yerself, over and over until you know the monitors, the position, what sounds right and wrong and good and shite.
Also, consider a grot-box, a Auratone or similar, and do remember to try your mix in mono.
FWIW, I mix on Tannoy 6.5 PBMII’s and I always check, mono and stereo, in my Auratones. (Problem mixes – usually someone else’s raw tracks – might also get checked in Optimus 7’s at the mix position. My home (3) and vehicle and portable stereos have not caused me to change a single mix since I started this approach.