Use a brown paper bag (and a banana!) to ripen avocados according to your schedule. (Ripe avocados can be stored for several days in the fridge without overripening.)
For better flavor, use a molcajete or mortar and pestle to crush the aromatics for your guacamole.
Salt your chopped tomatoes to give them superior flavor, appearance, and texture in your salsa or guac.
How the Science of Salt Can Improve Your Tomatoes