When you get to the first shiny layer, peel a paper thin layer off. A knife or sharp fingernail should do it. If it is a chunk, it is too thick, try again. You should be able to put the coverslip and stain on as before. You can examine many plant leaves by bending them and peeling off a thin outer layer.
Geraniums work very well.
Now look at some pond water, or a stagnant puddle. There is a whole world out there you may not have seen before. This is a fun lab to involve your family or roommates. Don't forget to write this lab up using the scientific method and send to the instructor using the icon in the top left of this section. See sample in Lesson 3 Scientific Method.