I drop the 2x4 out in front of the tire, before I get out to refill. Gas cap off after I get out. I like to run the pump on low speed (first click) until it shuts off automatically, then wait a few seconds and top it off.
If you are spilling fuel, then you might just listen to the gas level rising in the filler neck and shut it off when it gets to the top. I don't think I have spilled any gas in a very long time at a gas station, years at the least, maybe a decade.
You don't want to fill it to the top of the filler neck, about 4 inches below keeps the evaporative emissions system from being flooded with liquid fuel which will destroy the charcoal cannisters contents. You can probably see the small vent hole in the top of the filler neck very close to the restrictor for unleaded fuel.
Always fill when you have somewhere to go that will use enough fuel so the chance of the fuel expanding into the evap emissions circuit is eliminated.
An example would be filling and immediately parking on hot asphalt in summertime. The fuel in the tank is typically around 60 degrees fresh out of the pump. Heat that to 90-100+ degrees and it will expand and flood the evap emissions vapor line. Repeated events like this could ruin the charcoal cannister that is supposed to hold excessvapor pressure in suspension, to be purged the next time the engine is started.
regards
mech
http://www.aa1car.com/library/evap_system.htm