all the antialiasing is done by hand. I don't really have a cheat code I can give in a small paragraph, all I can say is to practice and get a good feel for the smoothness.
There is no dithering on this piece, unless you have a different definition of dithering. This piece was done entirely by hand. The only tools I used were the pencil tool and paint bucket tool.
If I was to use a tool for dithering, which is something I've only ever done once (in this piece http://pixeljoint.com/pixelart/117552.htm on the cross beam of the bridge support), I would use a brush with a 50% aliased mode which will create the iconic dithered checkerboard. You could also use other percentages for different shades. All this is seen within the piece I linked. If you have any further questions, please feel free to dm me!
>Whatever it is
Obviously it is "element".
But anyway, the dithering on this piece is très cool. It really shows how you can get some oddly-angled lines to come out with correct dithering. Question: is it completely manually done, or is there a tool that you use? Not that tools are bad, but I wonder whether that kind of dithering pattern comes out of practice with individually placed pixels or from a program, and if the latter, what program did you use?