Look around you in the room you are in right this minute. Start with something simple like a chair or your cup of coffee. It doesn't have to be big and elaborate. Just go with it, get to know the feel of your paints. See how adding more water works or less. Really look at the light source and where the shadows are forming.
Try and enjoy the process. You could take a class, but if you are like me, and prefer your own company when it comes to distressing with art, then welcome to the world of YOUTUBE!
Below is an older British artist that not only helps you get started, but his voice alone totally relaxes me!
Now he clips his paper to an easel, I personally like to use painters tape and tape it to my drawing table where I do my painting, which then leaves a good clean edge. But remember to enjoy the process, and that no subject is off limits for your watercolor paintings.
Even a mug of coffee can look exciting!