Here are a few sketches I did a while back from photos taken around Dublin.
This was done with acrylcs. The photo was of a building on the grounds of Malahide castle.
This sketch above was done with oil pastels on plain sketchbook paper. The one below is of the same image but I used Gesso on the paper for the first time. I liked using the oil pastels on the primed paper, much smoother and easier to apply and blend.