i am only a week or 2 into all this, but this is my experience.
i astral projected the first night after reading erins stuff on it, i guess cuz i was so excited and what not; i wasnt ready. the sky started spinning and i got scared and gravitiy was shifting all over the place. i heard this crackle of energy like transformers or somtthing, and i heard many voices, half whispers, in my ears. my body started lifting off of the bed, especially my legs, and i was super scared. i then allowed it to happen and let it be for a moment, and i peeled out of my body and a distinct voice started talking about death and weird stuff that i dont fully remember, at which point i got very scared again, dropped back into my body, and that was that. looking back i think there were a couple reasons for all that.
i think i was vibrating at a low frequency because i was so scared. i think the voices were astral beings of evil messing with me (not in a joking manner though). also i did not know about protecting my aura and my energy. that is one topic i feel that erin should write more about, as i have discovered it is very very important whenever meditating, or even just being in a crowd.
the next day i went to my local psychic and she took one look at me and told me i was playing with dangerous stuff without any knowledge (paraphrase) and she taught me how to protect my energy.
anyways sry for the long post. as for my spirit guides i am starting to feel a presence in the dark like i did when i was a kid (my spirit guides i think). its a little freaky, so i can understand why they havent revealed themselves to me yet. with time will come understanding.