Using the real hardware. Emulators are great, i tried them a few times, but it's never like the real thing. Not to mention the compitability problems.
Picking up St's is very simple. Not long ago i picked up a Mega ST 4 + 512ST + 2 sm124 (ok useless for games and demo's) + printer (useless too really) for a bunch of flowers. A week later i found a Falcon030 desktopper with coprocessor and eagle 32 accelerator + mega ST 4 + 2 megafiles + somesort of midi rack case with only a falcon mainboard but with co-processor + a couple of monitors for 50 euro. And that cos the (new) owner was stupid enough to connect a SM124 to the keyboard connector and thought the thing didn't work
I still have to convert the connector in such way a mega st keyboard works on it though, since the formal owner created some non working converter for it.