i rarely use the undo key on the computer actually, i tend to work it around because thats what im used to, unless i do something catastrophic.
as far as spilling ink goes, its good practice to try and work with it with more ink and white paint. at the very worst, youll look like you are trying to rip off frank miller
one of the beatuies of pixelart is that you can figure a basic composition in a small area and then enlarge and use the basic regions for your sketch (which a tablet hels with but a mouse can accomplish). i personally begin with a pencil sketch for larger works (examples in this forum: pirate girl, bronze), but the smaller or more heavily stylized ones (examples in this forum: forest princess, tactics character) i usually work straight on the computer. monsters are a mix and backgrounds are always pure pixel
