First Thing

Deep listening is both active and receptive at the same time

The active part lies in paying close attention to all that the person is saying
The receptive part lies in taking all they say into your heart to get a deepening sense of how it really feels to walk in their shoes and deal with this situation... from their perspective

Second thing

Closely listening in this way is not always easy at first but it is certainly hugely rewarding especially in the long term

When practising it you release the urge to interrupt with our own views as this is not the space for that. Reserve that for another time
Your full attention here is on the other and their story with all the interest, empathy and support you can provide in helping them to relate it.

Third thing

The secret lies in staying fully present

Focus both on what the person is saying and how they are saying it - the tone of their voice, their facial expressions, emotions, individual mannerisms and even the pace of the voice itself

Fourth thing

You genuinely seek to know and hold a space for how they feel

All this shows them the true compassion you hold for them. It also helps you to remember and best understand all they have to say

and finally

you simply listen to learn

in this space any response you make is prompted purely by your wish to know more and intended solely to advance and deepen your understanding of their situation. No question or comment you make here is designed to project, inject or defend any strongly held view point or position of your own