How to peen the humble unassuming rivet. It's a little more complicated than bashing it with a hammer a bunch, but not much.
Step 1: Supplies
in this picture i have....
-a 5 pound anvil
-a metal punch
-a small ball peen hammer
-2 pieces of metal to rivet together
-and a roofing nail.
obviously you don't need to use these tools specifically. a drill works as good as a punch, and the anvil can be replaced with any anvil like object. I regularly use a big ass block of steel i found at the side of the road, a chunk of railroad track, a 15pound lead sinker, or in a pinch I've even used a brick. just for some ideas
as for the nail, i usually use 6d nails from the hardware store if i'm riveting metal to metal and use the roofing nails when i;m attaching leather to metal.