This is just an example of many photos I took in the lab of a Gram stained bacteria. 100x magnification, Leica microscope.
Part of the reason the focusing is not all that great is because I forgot to reset the diopter correction back to neutral (I am slightly near-sighted). Essentially, the idea is to take a camera (I used Canon PowerShot A75), turn off flash, and hold the camera lens right up to ocular of the microscope. You might (or might not) get better results from turning on macro mode.
Overall, not too bad, although this one was taken with exposure of a few seconds, so it shows some hand shaking too.