Listening, or what some people refer to as "active listening," has gone a long way in helping me to succeed in my work and in my personal life. One thing that I've learned is that not everyone wants to be heard, particularly those who'd prefer that you not remember what they've said or written.
I never had any formal training in listening, but if you're interested in helping people in distress, then you ought not to be paying your bills or texting while they're opening their hearts to you. Though there are exceptions.
So I don't have any tips. A sense of humor helps, except for the guy who makes a joke out of everything. Nobody listens to him anymore.
A sense of perspective may also help. As well as an awareness of the context in which you're conversing.
When someone's looking for support, IRL, it's often not a good idea to tell them how much you or someone you know has suffered throughout their lives in response to their telling you about their present sorrows. Doing so often has the effect of the other person feeling as though she's been silenced. Or at least the sense that you think that her problems may not be as important as yours or someone else's. Let context be your guide.
Unless it's absolutely necessary to do so, I never interrupt. The more someone speaks, the more she lets you know who she is, even revealing things that she'd rather you didn't know about her, without knowing that she's doing that very thing.
People who listen will usually "remember that time when we were talking about emojis?" You won't have to remind them of a conversation that was important to you at the time. Then again, there are people who shut down when listening to someone who cannot control the content or the volume and amount of their own speech. No matter how important, the conversation will be forgotten as soon as the two people officially disengage.
There are also people who possess an irritating way of speaking that simply cannot be ignored, and that can overwhelm the content of their speech. If the person is someone you care about, better to find a way to listen rather than wait for her to get speech lessons, even as the figurative ice pick is being driven through one or the other eyeball. It's simply not right to fault people for either natural or acquired disabilities.
I also believe that we all know when someone is not listening to us. When this happens, you might try redirecting their attention by saying something like "Your pants are on fire." Like when a guy is sitting across from a woman on a first date, and his elbow is resting on the table at a 45 degree angle to his face, with a clenched fist touching his face, indicating that he's sincere about taking in your every word when, in reality, he couldn't care less. There is absolutely no cause for sitting, let alone conversing in this position. His blushing at his own secret disinterest in what you're saying, or as q result of his own prurient thoughts is a bonus red flag in this particular pose.
That's all I got, for now.