I have found it useful, when inhaling, to focus on my mental alertness, to really sort of 'sharpen' my awareness, and when exhaling, to relax the body. Don't do this constantly, but one in a while try alternating these two and it seems to help bring mind & body together.
Regarding cushions, I used to sit on a cushion but gradually got lower, sitting on blankets, towels, etc. and now I sit on the floor (well, if it is a hard floor, then on a mat or blanket).
I have also heard of using a telephone book this way, under some padding, and every day remove one page. when all the pages are gone you don't need a cushion any more.
My main problem is that I usually end up with one shoulder being a little higher than the other. This comes from years of lugging around a heavy shoulder bag, I think.
Profile Picture: "The Foaming Monk"
The Chinese characters are Fo (buddha) and Ming (bright). The image is of a student of Buddhism, who, imagining himself to be a monk, and not understanding the true meaning of the words takes the sound of the words literally. Likewise, People on web forums sometime seem to be foaming at the mouth. Original painting by P.Volker /used by permission.