Here are the slides used in class.
An immensely valuable study aid for you to explore is the Otterbein symmetry website that features a Symmetry Tutorial, a Symmetry Gallery with many molecules, and a Symmetry Challenge that takes you through point group assignment step-by-step utilizing an interactive flow chart.
You may also like to read the Lecture Notes on Point Groups as well as the following short readings: A simple procedure for point group classification., and Fackler's article on symmetry.
It is often convenient to use a flowchart when assigning molecules to point groups. Here you can download a typical flowchart for your own reference.
After you have done the readings and tutorials, test your understanding using these flashcards that have been tested for use with the Firefox browser.
For more practice, there is a further symmetry tutorial available at the reciprocal net website. Also, here are older lecture notes in presentation format.