One thing I've found handy is using a vst oscilloscope as a visual reference when programming the Virus. I used this while creating a more "vintage analog" saw tooth waveform for example. I adjust the waveform shape as well as the filter, eq, & analog boost parameters to get the waveform looking like I wanted it to look and sounding how I wanted it to sound. You obv want to do this with fx disabled and only 1 osc playing so you can see the waveform clearly in full detail as you sculpt it. Once you've shaped it as close as you can get it save that patch for later use as a starting point. I saved mine as VintSaw.
Working on a basic waveform with 1 osc playing and no fx, an oscilloscope (with the view stabilized of course) can be valuable for learning more about synthesis and getting a visual reference for how different processing in the virus affects the waveform. Try it out with the different character settings or distortion or whatever you like.
Download s(M)exoscope here free if you don't already have it!
http://bram.smartelectronix.com/plugins.php?id=4
