Drawing skills are an important skill for any designer, but especially for user experience design.
Whenever you attend a client meeting you should automatically start doodling, and ideally get up to the whiteboard and capture the moment visually for all to see. People tend to talk in abstracts and your job as a user experience facilitator is to help not only the client solidify their goals but help the team you work with understand the vision. So why doesn't this happen more? Well most people's first reaction to being asked to draw anything is "oh I am not good at that, I do stick figures only". Well guess what they work too.
Here are a couple of considerations of how you might go about capturing user experiences with sketches.
Firstly loose the detail. Yes people and hands are difficult to draw and we all struggle with them if you try to capture the details. If you think of people as stick people. It gets a lot simpler. Take for example these examples from Austin Kleon about how to draw faces. Communicating an idea doesn't need a Michelangelo rendering to get the point across.
Simplicity is key to communication, especially in meetings and when using a white board, because after all as your sketching you meant to be listening to the client speak and be ready to step back into the conversation. Anything longer than a couple of minutes work is probably too detailed and missing something simple about the concept you are capturing. Sometimes it is unnecessary to draw complete people, just hands work or a close up of a face. Just drawing objects helps, especially in UX where devices are just boxes(think the black brick that is every mobile phone), this means that you can convey a moment of interaction by doing a close up of the device and maybe just a hand gripping it. Again think cartoon style, I would even say that like Disney only use 3 fingers to represent a hand, it works fine it has enough information to express action.
These are the types of sketches you need to be practicing when you are doodling, these basic drawing techniques. Think of a action like holding a phone and try and draw it on your note pad. Think how you might draw a gesture such as waving, or pointing, action arrows help a lot in capturing motion. Study how others draw storyboards. I find that thinking about people as Lego figures helps, I always find that these simple characters can capture a whole host of interactions just by playing with poses and making a small additions to what they hold and how their faces look. People don't get represented much simpler than this, plus if you use the real Lego's you can practice drawing what you see.
What is critical about these drawing skills is to use them to help remind all in the room of the discussion that took place and allow people to review them at their leisure during the communication. Also, their value is in the storytelling of the experiences and touch points with end users and consumers. It gives you something to capture and share at the end of a meeting that helps everyone remember some of what was discussed, more than just a bullet list of notes. I always try my best to do more drawing in meetings and I think all designers should have the skills to draw what they are talking about as part of the communication process.