We bought tissue paper in pink, orange, blue and green. I cut it down so we had rectangles that were 10" by 9" each. Then I made a crease an inch from the top to make sure that we didn't cut the area that the ribbon would go.
The tissue paper was folded like an accordion and then we just cut it using exacto knives. The first few I ended up recycling because I wasn't too happy with how they turned out but after I did a few I got the hang out of. N "got the hang of it" right away and his turned out much better than mine. When they're mixed together maybe it's not too obvious whose are whose. :-)
After they were done (we made 42!) we figured out where we were going to hang them so we would know how long each string of them needed to be.
The top edge got folded down and I put the ribbon under the flap and just taped it down. I also added a small piece of tape to hold the papel picado onto the ribbon so they didn't slide around.
Then we hung them up for the fiesta!