Excellent advice. In fact, I've been working in photography for over 45 years and could still use such a class. One piece of advice I would give, though, is if you possibly can, splurge on an SLR. There's a ton more flexibility with them.

Black hides a multitude of sins, shadows being the worst. Velvet, velour, or if you want a bit of texture, fleece. I use dark blue fleece when I have an especially dark flower, but then one does have to watch out for shadows. For any background, a camera that can focus (and meter) on a spot (rather than a larger area) is vital, especially for smaller flowers. That's the downfall of many inexpensive cameras (including all but the best phone cameras) If you want to purchase a camera, the lack of capability of selecting spot-focus and metering is a deal-breaker.

Before digital cameras, you would put a white card in front of it. Maybe that will work. Do you use ISO/Aperture/F-stop settings or is it automatic? Focusing forward of the background to a lit orchid might work also if you do have those depth of field settings.