As a parent it is easy for us to be on broadcast, to tell our child what they should do or how they should feel. However, as our children develop their independence, we want to be in a position to give them advice for them to make their mind up with.
To start with you want them to feel comfortable talking to you, so it is important that they do not perceive the conversation as a threat. Ultimately, this relates to security, to be able to talk about being vulnerable we need to feel safe and able to trust. Whilst your children may absolutely trust you, there can be times (especially during puberty) where they are pushing against you and feel like they cannot trust you or that you are using this as a way to manipulate them or tell them off.
Asking them an open question and then remaining silent is a good starting point. Listening always involves one person being predominantly silent and in these cases it should be you. Some children respond to this approach quickly, others take more time and initially respond with a huff, sigh or rejection. These are to be expected and relate to the paragraph above about trust and safety. It may take you several attempts to achieve this and backing them into a corner often results in you being told what they think you want to hear. Sometimes, for those finding this difficult, doing this whilst you are both focused on something else means that it is a less threatening approach for your child.
Then listen. Respond, ask questions, use body language, but let them do the talking. Very often taking this approach helps someone to process or move forward, you may not even need to give advice, but you’ve been there for them. If you do need to give advice then explain their options (e.g. you could be feeling this, this or this; I think your options are to do this, this or this), but ultimately in this sort of conversation it is about listening to them, their views and what they want to do.