The first days of my marker challenge were centered around the theme of terrariums and plants. I decided to next move to something a bit more graphic, so the current theme is logos and badges. The plan is to do a mix of original designs and existing ones, but for now I'm doing some fanart of existing images. The first set includes the Lantern Corps rings from DC Comics. I felt it would be boring to have just one a day, so I paired them up.
In the first themed set, I did use various templates and rulers to help get curves or straight edges, usually for either the sketch or the final drawings. Those templates, especially the circle templates, were used a lot for this theme because there were so many circles involved. If I did it again, I would probably use the templates for both the sketch and the final inks.
Another challenge I wanted to address was getting some sense of form across in the rings, that they had raised and lowered edges within the insignias. I used simple darker strokes to indicate shading and a white gel pen or color pencil to do highlights. I might be tempted to come back to these later and try doing a better job at getting that depth across.