The most important fields in the public page activation are Title and Description. The title will be shown on the top of your public page, as a part of the URL to your public page, as a title in the metadata and will affect greatly Google ranking and how it will appear in Google results.

You can always change the title at a later stage, but, every time you do that, it will change the URL. You might lose all your Facebook likes and Google+ +1s when changing the title. So it is VERY important to think about that carefully BEFORE publishing your page.

A good title is a specific title, but not too long. Think about what users would enter as a search on Google to end up on your public page.

Good title examples:
Everything about PS4
Sites for movie reviews
All employment sites in US

Bad examples:
PS4
Movies
Employment Sites

Descriptions help users understand more in detail what your public page is about. That information will be stored in the meta-description and also has an effect on how people can find your public page.