This is a simple short cut for situations when you have a complicated landscape to draw, and you don’t feel up to it, or don’t have the time.
I recommend a wet-erase marker (like the ones that used to be standard equipment when using an overhead projector). These markers will enable you to re-use your window, along with ensuring that your sketch doesn’t smudge (as might happen if you use a dry-erase marker).
The basic idea here is to “trace” the scene outside your window. Really, that’s it. 🙂 What you get from drawing on a window, though, is a bit more nuanced.
2. Quick repetition. You can practice drawing that landscape over and over, with low-stakes (low pressure), and you can do it fairly quickly.
3. Train your eye to simplify. One of the most challenging things about observational drawing is learning to simplify a complex scene or object down to its essence. Drawing scenes through windows can help you train your hand-eye-mind combo to make choices about which lines are necessary and which details can be left out. This is a fundamental part of the drawing process. Drawing on a window means you are able to practice this decision-making quickly and often. And, you can see what affect your choices have on the outcome while the scene is still right there under/behind your drawing.
Once you have that window drawing, you have a couple options for putting that sketch to use.
1. You can use it as a guide. Draw on paper, basing your drawing on the decisions you made on the window.
2. You can take a photograph, and use that photograph itself as an image. If you do this, consider putting some paper outside the window (if that’s feasible), so that you have a plain background behind your image. Doing so will result in something you could potentially use as a coloring sheet, worksheet, or the foundation of a more detailed drawing or practice sketch.