Spread refried beans in the bottom of a deep pie plate. Spread guacamole over top.
Stir together sour cream and taco seasoning. Spread over the guacamole.
Add layers of cheese, then tomatoes, green onions and olives. Refrigerate for at least 30 minutes before serving.
Notes
My mother-in-law always prepares her dip in a deep pie plate (as shown here), but you can also use a rectangular 11 x 7-inch or 9 x 13-inch dish. Just keep in mind that the larger your dish, the thinner the layers will be.
I use refrigerated prepared guacamole for a shortcut, but you can substitute with about 1 and 3/4 cups of homemade guacamole.
For a heartier 7 Layer Dip with Meat, use the taco seasoning and 1 lb. of ground beef to prepare taco meat. Layer the cooled taco meat on top of the refried beans, and then prepare the rest of the dip according to the recipe instructions (using plain sour cream).
I prefer the Old El Paso Mexican Style 4-Cheese Blend for this recipe, because it adds great flavor complexity to the dip. You can substitute with any of the other Old El Paso shredded cheeses. The Mexican Taco Cheese and the Finely Shredded Cheddar are both favorites around here as well.