Environment Design Rocks!

[Bookend]

@Book.  Why are you after more contrast in particular? That reference image, if anything has too much. It is overexposed, especially in the sky and is actually a perfect example for this exercise why photographs don't do "reality" well.  

If I were you I would pay more attention to the notes, and your own observations while at the scene. Did you take good enough notes the first time to be able to recreate what you saw? THIS is actually the whole point of the study, and what you want to capture. The reference is just there to jog memory, not be relied upon as totally accurate for the lighting conditions as they were.

If you keep going back to the same scene, things will drastically change each time since it is outdoors, so I'm not sure if that will help at all.

The value sketch looks fine to me. But again, you might be relying on that reference photo too much by blowing out the sky a bit too much., it's a good start anyway, you can adjust as you get into colour.

I meant more stark differences in the values-- More darks, in particular.  As you say, it's really blown out and bleached, and very same-ish..  So I was concerned that it wouldn't be a good reference point.

And, like I said, I can't go back to the spot because construction work is being done in that area and they put up big metal fences.  Really inconvenient.  I am considering going out and sketching up a different place, anyway..  I'm not too satisfied with the photo or the notes I have on it.