the ouija board is, as most use it, the metaphysical equivalent to unprotected sex, because you're inviting a spiritual entity without any divine authority or control over it, and with nothing to bind it or protect oneself. in traditional operations of spirit evocation the world over, there is usually a magickal circle or square or mandala, the magician stands in to protect himself, or at the least there are talismans and divine presences that are activated to protect him. in medieval goetic demon evocation, not only are the circle, talismans, and divine authority activated and invoked, but the demon being conjured is called into a triangle outside of the circle, that further binds it away from the magician, like a small prison cage. -all of this is very different from the middle school sleepover party scenario that the ouija board often finds itself in. that's not to say you can't use one effectively, if you know what you're doing.
first, erect a circle, about 9' diameter. this can be drawn in chalk, laid out in rope, or made of salt. it helps if you write divine names around it too, but that's more advanced. once its set, empower it to set the place apart as sacred and unbreachable by anything willing you harm, which is often done with intense visualization, and/or a mantra or prayer.
light a candle and invoke divine guidance and protection into the light.
burn a good incense- don't use the sticks, actually burn the real deal on a coal- a good all-purpose combination is frankincense, myrrh, and dragons-blood. other things can be added depending on the planetary associations of the spirit being summoned.
these things being done, make a petition to deity to grant you the power and authority to call and control your chosen spirit. then begin the conjuration.
when you feel like you're not alone any more, you aren't. it may manifest somehow, but usually (for me) its mostly an intense feeling of not being alone any more, or of something looming just over my shoulder- sometimes the air pressure changes suddenly and my ears pop, or the temperature drops, or the candle flame gutters violently.
when you're done asking your questions, make sure to dismiss the spirit thankfully, and make a closing prayer to deity, thanking it for its support of your operation.
final notes: it often helps to pray and fast the day before and of the operation, or for longer depending on the power of the spirit being called, to purify oneself for the ordeal. also, dont' ever sacrifice or give anything, or make any pacts- approach the spirit with an air of authority.