I know I've talked about "How to Draw Nothing,"
but have you ever tried to draw WITH nothing?
Here's what I mean: Look up in front of you right now.
Find something that has an edge - a window, a plant, an object. It could be close, or far away. A building, a car, a piece of furniture.
Now, take your finger and up in front of you, trace around the edges of that object. Notice how "big" it is in your vision, as opposed to its "real" size. See how the edges run into each other. Is the object squiggly? Has it got hard edges? Are there places where the edges are hard to see because there's something else in front or it's blurry? This can be true when tracing the leaves of a tree, for example.
After you do this a few times, you'll find you see things differently - relationships between objects stand out more, for example.
You will also find out some things about what interests you: What do you tend to trace? Do you like certain shapes more than others? What about colors or textures?
And don't worry about doing this in public - everyone's walking around talking into phones mounted on the sides of their heads anyway - you won't look weird.