@justin You can do tighter spacing in containers and raised beds. Usually seed packets specify spacing between plants and between rows. What I do for raised beds is take the plant spacing, add about 25%, and then use that for overall bed spacing.
eg one of my broccoli packets says plant spacing is 18” and 2-3' between rows. 18+ 25% is roughly 22 inches, so that's how far apart I'd put each plant.