Resources for
Collection Methods
Collection and culturing is not difficult for many microscopic species.  My suggestion to you is to find a water source, scrape the sides and bottom, and if there are plants in the water, pinch off a leaf or two to keep with your sample.  Be sure to give your sample sunlight, as the producers must be able to produce!  
   
The following websites have some good tips:

An Introduction to Microscopy (Follow the links: Pond Life Identification Kit - how to. . .)

Pond Dipping