When you hike in Sedona, you'll experience a strange but rather common experience. You'll see an interesting rock formation that looks like a five-minute walk, but it'll end up being an hour's journey. Or, just as likely, a formation that looks pretty far off will be only a short hike! As with much of the arid Southwest, illusions with distance result not only from the clear air but mostly from the lack of a scale reference.
A scale reference can be a human figure, a house or even bunches of prickly pear diminishing into the distance. Anything that has a size that we are familiar with will work. In my own paintings, I've used all the tricks - even a pair of ravens whirling around a summit. It's important to let the viewer know how big (or how small) a rock formation is. Just drawing it accurately isn't enough.
In the accompanying pastel sketch, I used juniper bushes. Around here, they're all around the same size - about the height of a human. But not everyone is familiar with juniper bushes, and I have seen some exceptions which are twice as high as me. To make the sense of scale even more successful, I might have put in some prickly pears, the pads of which would become smaller and smaller as they got closer to the rock. Or maybe even a rock climber, rappelling from the summit!
By the way, due to technical difficulties, I wasn't able to use my tripod for this sketch. I ended up holding the board in one hand while sketching with the other. Even with a minimum of equipment, you can get good results.