If you are using the machines in the states cluster, be warned that using images on the network drive (i.e. on your account) can be risky. Small interruptions in network flow can damage your image. It is recommended that you work from images in the /tmp/ directory on whatever box you are using and then replace those files back onto your account for storage.
Like the coweb says, the Cases page is extremely useful. Consider that part of your grade comes from reuse of existing code; this could conceivably be code from the cases page.
Also, consider that–in the past–students have been able to get extra credit by contributing help files to the coweb. One of the easiest ways to write such a tutorial is to discuss a common bug or difficulty and how to circumvent it. Therefore, a lot of things you may find yourself struggling with probably have answers buried somewhere.
Learn the squeak debugging system, particularly explorers and inspectors!! The debugging system may be my favorite part of Squeak. If you want a really quick lesson, come by my office hours.
But most important of all, backup your images frequently. I wrote a three line unix script to dump a copy of my image and changes file every so many minutes when I took the class. That may not be your style, but I highly recommend hiding versions of your code somewhere on your machine so that you will have an uncorrupt copy.
This is my fifth year at Tech. In addition to CS, I also study philosophy and literature. I'm trying to write.
I am an Atlanta bum, check out my guide to Atlanta (on the Personals page). It hasn't been updated in years, but could still be useful.