So for Shamrock mouse I sketched him right in adobe ideas starting off in a light blue pencil. I then added a second layer to go back and refine the initial sketch in grey. ( I love being really sketchy). Then I added another layer and began to ink over the sketchy lines in black. I sometimes find it easier to ink lines past the actual sketch lines. This makes it easier to get a nice flowing line and I made sure to keep them all on different layers so clean up is easy and you only are erasing what you don't need! Lastly I go to another layer and start adding more details to the shoes hat and shamrock. One key thing is I use different size lines for different parts of the mouse. I used a 2.5 size pencil for the eyes and mouth and used a 3 and 3.5 to ink the rest. I always seem to change my inking style, sometimes I use a lot thicker lines, some thinner and some even sketchy!