I make the same sort of diagrams over and over. Here I list fragments of dot code that have proven useful. website 
strict will filter out duplicate arcs.
strict digraph { ... }
make all nodes filled with color.
node [style=filled fillcolor=gold]
use a short node name and a long label.
sfo [label="South\nFacing\nOutdoors"]
use a box for some nodes.
rnnnnny [label="a slug" shape=box]
favorite colors, favoring svg compatible names. doc
gold palegreen lightgray