Put a drop of water from a pond, puddle, or hay infusion under your microscope, and you have a new world to explore, filled with a variety of strange and amazing lifeforms. Identifying them can be a huge challenge, so I am setting up this gallery as a starting place, to point you in the right direction for recognizing some of the more common organisms.
For any source, try collecting drops from different places. Examine a drop from the bottom, one from the top, one from a leaf or stem, etc. For each drop, try to get at least a couple of bits of debris large enough to see. That will make it easier to focus on the thin film of water between the slide and the coverslip.
Alter the light as you explore each drop. Making the light brighter or dimmer will show different things, and it may be easier to spot an organism with one kind of lighting or the other.
Protists are single celled organisms that are not plants or animals. They are a separate