Inking
For me, inking tends to be the longest step in creating digital art. This part of drawing is when you take the rough sketch and slowly define every line with smooth, conscious lines. This takes time and tons of undoing work, but will eventually leave you with nice crisp linework.
When I organize my layers for this part of the illustration, I tend to split each body part into it's own place. This allows me to layer up different parts of the drawing and easily erase overshot lines. After the overall lining is done, I like to do some final sweeps for stray lines and odd shapes. Once the piece is ready, I move all of the line components into a folder named "line comps" and copy/paste them to a new layer, merging them all together. This is now the final lining of the illustration.