to reduce potential light leaks (if you don't want them), put a piece of gaffer's over the counter window, and fold over a small piece to make a "pull tab" to pull the tape back and view the window when advancing frames. The recent 120N models are relatively light leak free except this window.
Additionally you may want to make similar tabs to place on the right and left hinges that secure the back, as the back can easily come off, especially if you are using a neck strap. Other than that, shoot a few rolls to get used to how the Holga frames your subject.
Have fun...