Most of the time, my answer is "use a tripod". The rest of the time, I add "with a dolly". Handheld shots are way overused, IMO.
If you're determined to do handheld shots, my advice would be to start by experimenting with shooting the shots without a Steadicam. Lighter modern cameras with good image stabilizers (Canon's optical image stabilization, for example) can often do a remarkably good job on their own.
Finally, in most cities, there are outfits that will rent out Steadicam hardware on the order of thirty or forty bucks a day (sans operator). It might be worth trying it out just to get an idea of what they can and can't realistically do.