I try to spend some time doodling every day. It's not just a way to pass the time. It's practice. It's also a meditation of sorts. Doodling has helped me concentrate during boring meetings. It's also been an effective way to take visual notes.
When I'm trying to draw something specific, I tend to be overwhelmed with anxiety. I work in pencil and erase constantly. I doubt myself and feel inadequate. Nothing is ever quite good enough. I focus on the faults. It's painful.
When I doodle, it's like I'm a kid again. I can play and experiment. I'm drawing for me, for the fun of it. I'm often surprised by what comes out. I work in ball point pen, so there is no erasing. I have to deal with whatever I draw and how it turns out. I like the ball point because I can start light and build up. I can work and rework a doodle until it's something cool. Sometimes I start out drawing one thing and it's not going great, but I notice that it looks more like something else so I turn it into that other thing. Doodling is reactive, an interaction. I generally do not have a plan when I start. I draw a circle and build out from there. It becomes an eye. The eye becomes a face. The face grows 3 more eyes or some fur, or some tentacles or whatever.
Sometimes what comes out is lame. I don't always tap into the magic, but the more I practice, the easier it comes. Sometimes I slack off or go on a left brain binge, working on the website or something. I get stiff and it takes some pushing to get it back. But it always comes back.
I've been keeping a sketchbook for years, over 25 years now. I look back on old sketchbooks and cringe a little. I've improved over the years, but at one point that was the best I could do. I'm only better now because I didn't stop.
Most people stop drawing because they tell themselves that they are no good at it. They think it's a magical talent other people are born with. The truth is that everyone draws when they are young. Some people just get more attention for their drawing and stick with it. Maybe they have the kind of temperament that allows them to sit quietly by themselves, and get enough satisfaction from it, to struggle through not being that good at it.
I think that anyone can learn to draw if they can get over the self criticism. That's where the doodling comes in. If you can make drawing fun and free again, you can practice enough to get good. It's good to sketch from life, too. It gives you the base for the drawing from imagination, but even drawing from your favorite cartoons could be a good start.
The doodling serves to keep me in practice for when I do want to sweat through a "real" drawing. It gives me more confidence.