You can focus on their sigil and talk to them in your head or out loud that way. If they don't have a sigil then just speak to Them when you're in a quiet and private place.Likely, if you don't know who your GDs are, *They* will come to you, when they deem the time is right. They will send signs and coincidences, just be open and aware.For example, one of my GDs is Lady Marchosias. When I was very new in Spiritual Satanism, I kept hearing a young woman's voice inside and outside my head, but kept putting it off to the enemy, having prior experience with them before coming to Lord Satan. Eventually another person who she looked over posted about her on the JoS Yahoo groups, and something clicked with me, when he/she mentioned how Marchosias' voice sounded. This was one way that She let me know that She was my GD. I didn't trust her voice upon first hearing it, because her tarot card did not show in a tarot spread I did to find out my GD(s). But now I know. ^_^In the meantime, it's important to focus on working for and strengthening your relationship with Lord Satan.
I am aware of the fact that everyone has a guardian demon, but how do you go about contacting them or actually speaking to them?