This wood pin assembly is a good way to slot legs into the table. The pin is big enough to hold the table in place while not breaking. If I have trouble slotting a table, I could use this slotting technique to effectively create a table.
Here's a simple project to bring order to the chaos: a door-mounted storage rack. You can modify this basic idea to organize other cabinets too. A complete materials list and assembly diagram are available here Cabinet Door Storage Rack.