As I'm sure most of you know, there are many ways to cast a protective circle or create a magickal space. I'm going to list only a few. Feel free to comment with your favorite way!

Directing Energy via your Power Tool of Choice:

The Forefinger of your Dominant Hand

Wand

Athame

Sword

Staff

Create a Physical Border by Tracing the Outline of Your Circle Using:

Salt

Holy Water/ Florida Water

Dirt (from a place that carries energy to enhance your magick ie your backyard, a hospital, a graveyard etc.)

Crystals

Candles

BONUS: When practicing with others, everyone can be included in the casting of the circle. The lead practitioner places their hand into the hand of the person standing next to them in the circle while saying "from my hand to your hand, the circle is cast" Then that person places their other hand in the next person's hand repeating the phrase and so on all the way around until the circle is complete and the lead practitioner declares "we are now between worlds" or whatever your group prefers.