Inspect the form of the succulent to note any particular characteristics. The Agave Americana, for instance, grows broad, flat leaves that reach up to six feet long from its base. It also has points at the tips.
Write down the location where you find the succulent. For example, the Century plant is common to California and Texas, while others like the Cholla cactus are common to all southwestern deserts in the U.S.
Look to see if the succulent is producing fruit. Some varieties like the Chainfruit Cholla grow spineless, green berries that connect together like chains.
Watch to see if the succulent produces flowers and note when you see the blooms. For instance, the scarlet blossoms of the Claret Cup show up from May to July.
Take a picture of the plant. Bring the photo and your notes to a garden center to get assistance identifying the succulent.