Make sure it's very FINE sandpaper.
I also edged around the pieces with gold or silver paint before shrinking. For earrings, they really add a touch of bling!
Make sure you use a hole puncher to punch holes in earrings (for jump rings & ear loops)
before you shrink. It's virtually impossible to put holes in after firing. Leave enough shrink material above the top of the ring, so the hole will be sturdy enough after firing, without tearing or breaking. BUT, place the hole high enough so you can fit a metal ring through it.
For some designs, you do NOT have to fire the dinks completely flat. I took some out of the oven while they had shrunk some yet were in the "Pringles potato chip" curvy phase & hadn't flattened all the way yet. They will be bigger, thinner & not quite as sturdy, (so scale designs accordingly) but for earrings, which can be more delicate, the wavy dimension was fun.
I pre-made several designs for the gals, so they could see the before size vs. the finished results. Also, they could compare the look of markers to colored pencils, to paints. Fine point black Sharpie permanent markers work great for adding squiggles, lines, names, etc. it's a very saturated black. They could also see if they wanted fully flat or slightly wavy.
To get permanent marker off hands or clothes afterwards, have a spray bottle of hairspray nearby. It disolves the permanent ink.
I had photocopied basic shapes like squares, circles, triangles, diamonds, stars, etc. onto paper in their preshrunk sizes, so they could easily trace them and get the finished sizes they want. It's hard at that age for the gals to picture the ratio of shrinkage from before to after. They don't want to end up with an earring or charm the actual size of a Pringles chip.
