Drawing thumbnails/initial sketches and storyboarding is my fav part. I tend to see my story unfold like a show/movie and attempt to capture the 'keyframe' moments for the boards/panels.
The tedious part is actually building up the characters (shapes, anatomy, proportions) and compositions (not just how characters/objects are arranged in a panel, but also how the panels are arranged on the page) but since I'm trying a more vertical format, I've somehow been having some difficulty/distaste for it, but I'll figure it out eventually, just a matter of patience and practice)
Coloring has always been a pain, but I have been experimenting with rendering and I'm eager to try some new things out in later comic eps (painterly backgrounds, maybe) but I'm not sure yet. Could be too much work for the moment. But I'll still be doing more experiments off to the side.
*lots of 'but's in there...gotta work on that XD