A good substage condenser is essential, and the old Zeiss, Leitz, and Bausch and Lomb microscopes have them. That's the key to this kind of microscopy. You can build a base for lighting out of spare materials. Two or three colored filters will be helpful - blue, green, red, or neutral density . They ought to be relatively transparent.
Filters create electronic noise, the deeper the filter, the greater the noise.
The next item on my desk is a Bausch and Lomb stereozoom 5, that is, a dissecting scope found routinely in most labs from Junior high through advanced research levels. This has a transilluminated base, but if yours does not, you can make one. A box, mirror, and piece of glass is about all it takes. AO zoom scopes are excellent for video mcroscopy or digital cam work, as well. The best I've used yet is the Wild M7.