The only way I've been able to communicate with the spirit world -- in terms of real conversations -- has been through Spiritualist mediums. Although I have personally received an occasional clairvoyant image, while attempting to do so: and also once received a totally unexpected clairaudient message that saved me from an accident.
I also believe that the spirit world talks to us all the tim in ways that we don't recognize. I always hear myself thinking little reminder sort of messages. . . 'did you check this? did you remember to do that?'
I suspect that many more of these messages are coming from spirits than we realize.