I practice my "hearing" of spirit guides with chanting of mantras. It is work with the sensory experience of sound. I usually start with an invocation for the guide I wish to connect with. Let's take Kuan Yin again for example:
I bow to Kuan Yin
Whose white body is uncontaminated by fault
Whose head is adorned by the perfect buddhas
And who's compassionate eyes watch over all beings
With this invocation, I repeat her name, I humbly recite her prayers, I focus on her energy of compassion, joy and equanimity. I let her mantra just echo in the background. This will bring in her vibration frequency closer to me, allowing me to "hear" her.
The verbal connection I make with the guide is a pure and non judgmental communication. It doesn't carry on like a human to human conversation in the sense that it doesn't go back and forth. When I "hear" a guide, I usually hear a word or a direct phrase, then silence. The word or phrase is very clear and unmistakably coming from the guide. I don't filter it but I try to find the appropriate human way to communicate it. It may not make sense right away, but give it time and the message will become clear.