i use a few different dead blow hammers, electric double cut shears, dimple die for dzus tab buttons, right and left tin snips, 4" grinder with sanding wheels, lots of straight edges and sharpies, and dont forget to know someone who has a sheet metal brake.
use Dzus tabd if you can it is more than worth it when you have to clean the car or remove a panel. they are about $3 for the tab, button and spring.
i use .063 aluminum from the metal scrap yard. its cheaper than new and it only has water stains on it you can scuff off with a scotch brite pad.