There were several stages to the Homemade Peacock Costume Idea. I made everything except the corset (this, I only adorned).
The tutu: I bought approx. three yard of tulle in each gold, royal blue, and forest green. I cut each into strips- 15 inches in length, 4 inches in width (give or take a few). Taking a strip of each color, folded in half, I then knotted it around a piece of elastic (measure the length around waist first). Repeat the process until you've run out of tulle. The elastic will be stretched throughout the process, so make sure to take off a good 3 inches, or maybe even more. My elastic width was 1 inch, but a thinner one would have worked just fine. Sew or glue the ends of the elastic.
The bodice: I used an old corset I already had. I cut the eyes of the feathers, and hot glued them onto the fabric. For this part, I wish I would have bought more feathers. I only had approx 15ish clustered around the front. But I would have really loved to have them all around the body of the corset.
The tail: Everyone's favorite part! And also, one of the most time-consuming ones. I bought approx. 100 feathers, 40"-50" in height. Using a piece of cardboard (measure it so it fits your back), I then glued the strands onto the board. I cut the stems into different heights, so the eyes could be seen. I repeated the process (to a lesser extent) on the other side of the board. I wanted people to be able to see the feathers from both front and back. Wrap a piece of cloth (I used a bandanna) around the cardboard. The point of using the cardboard was to be able to slip it into the back of the corset. Without the bandanna the stems kept getting caught in the interior fabric of the corset. The bandanna smoothed that out.
Misc: I bought some cheap eyelashes online, and attempted smokey eye effect to great success.
I was really pleased with the costume. If I ever reuse it, I'll re-do the corset to include more feathers. The whole thing was completed in approx 2 weeks. Ten hours on the tutu. Another ten on the tail. But it was great fun, and everyone loved it.