If you are really an "absolute beginner", it might not be bad to practice drawing simple three dimensional shapes. Cubes, spheres, cylinders, and so on. They are fairly simple, and yet take some skill to get them look convincingly 3D. And as you get better at that, you'll find it'll help drawing other things since pretty much anything can be visualized as a collection of these simple shapes. Plus, simple shapes are great for learning perspective and shading.
Beyond that, I'd say look at lots of references of whatever it is you want to draw. Myself, I find it helpful to simply look at things as if I was going to draw them. Even if I don't actually draw them. It's basically the process of really paying attention to the shapes and textures and so forth. By committing these things to memory, you'll have more to pull from as you draw more things.
And of course, actual practice is always a good thing.