You MUST try to identify the organisms you see in your water sample by using the images and descriptions you find on the websites. Take a look at several of the websites before you decide which one you want to use first.
Pond Water Critters ID page
Pond Life ID kit
Virtual Pond Dip
AAAS Pond Water A Closer Look
Pond 2 – Life in a drop of Pond Water
Once you think you've identified a microorganism you may search for other images or videos of it online to confirm your identification.
For example: https://www.youtube.com/watch?v=fmwN_mD7TvY
Also try to identify any organelles you can in the microorganisms you observe. You may see nuclei or flagella or other organelles.
Flash Animation of Cells to DNA – Compares Eukaryotic cells to bacteria and zooms from chromosomes to chromatin to dna.
Cell Size and Scale - interactivehttp://learn.genetics.utah.edu/content/begin/cells/scale/