In case you don't know how to make circles, follow this guide. You'll eventually learn how on your own.
A graphical representation of how dwarven terraforming with buildings and mining works.
A flowchart including various industries, their products, how they relate to each other, and what is required to do/make certain things.
Dwarf Status at a Glance
A visual guide to what each flashing icon on your dwarves means; much easier than looking at each individual dwarf and sorting through their status.
An informative chart detailing the finer points of the metal industry, smithing, and furnace-ing.
Metals and Ores
A chart detailing which metals come from which ores, and which alloys come from which metals.
Pump Stack: Top View
A companion illustration to the original one, detailing the pump stack from above.
A basic outline of how to make a sphere over multiple Z-levels. The basic thing to remember is: just stack circles of larger, then smaller sizes.