To make this Pinata costume, I just bought an inexpensive plain dress and used fabric glue to attach streamers. I unrolled enough streamer to cover the front part of the dress when it was on and cut the height of the streamer into strips and left maybe a third of an inch in tact so the whole streamer would still be in one piece.
I then glued in tact part of the streamer onto the dress, (i started at the bottom of the dress and worked my way up) and repeated that process with about 5 different colors of streamers, making sure I did two strips of the same color every time. Also be sure to completely cover the glued section of the streamer with the fringe of the next streamer so you wont see any of the gross warped fabric glued part. Once you finish the front then you do the back the same way. It might be easier if you have a friend help you glue the back streamers on while wearing the dress especially if, like me, you have a big rear that changes the length of streamers you need for that section.
the horns I made by hot gluing tiny plastic cups to a cheap headband. I also covered the cups by cutting the length of a streamer in half and then making the fringe like I did for the rest of the dress. I think they came out super cute, it was my favorite part of the whole costume. That and my tail, which if you look closely at the picture you can see. It was just some fancy ribbon I got from the grocery store in the gift wrapping aisle.
One thing I do have to warn about with this costume is the importance of staying away from anything elastic or stretchy when buying the base dress, once you attach the streamers it will no longer give AT ALL. This is something I learned the hard way. the plain dress I bought was completely elastic so it took about three people to help me get the dress on and off without me completely ripping the streamers and ruining the dress.
It was defiantly worth it though!!! My costume was a hit at my Halloween party and everybody was amazed that I made it myself!