When studying the Old Gods, remember the Wiccan saying: All Gods are one God; all Goddesses are one Goddess, and together they are one.
This does not mean that Pagans believe or see God as the Christians, but they (Wiccans) acknowledge there is one Prime Creative Source of po wer that brought everything into being in the beginning of all things. Scientist call this the Big Bang theroy.
From The Magick of the Goddesses and Gods by DJ Conway
Invocation is an important part of the ritual. You can use what I have listed here or be spontaneous with your words. Feel free to rewrite these words to your liking. We can't all be the same =) Most of these are taken from Scott Cunningham books.