I look at the ouija board as a tool. I personally use this one:
I know it's a little corny looking, but everything is in a circle so I can us a pendulum.
I first ground and center, ryan a circle. I do a protction prayer/ritual before hand. I alsoclose the circle and recenter myself.
When it comes to closing the "portal", closing the circle should do that, but I like to pirigy the room and my tools once in a while. Also, if something went wrong, or seemed out of place, I would definatelu do it all right away.