Just recently got into this game and then realized that I have the whole Cosplay!
The wig I got from cosplaywig on ebay back in 2013 with two long clip on pigtails. For this, I wore the base wig and purchased a shorter black ponytail clip on extension.
I wore the same uniform that I did for my Sakura school variant, which was purchased off of Milanoo.
Tights? I got them at a CVS store. Yes, they also sell clothing.
And shoes are these black sneaker-like slip-on athletic shoes.
For my envelope, I just took a regular white envelope and draw a heart in the middle. I used some hello kitty art pens to color in the heart to give it more of a "lovey-dovey" girly effect. On the back, I wrote "せんぱい" (Senpai), implying that the note is for my senpai!
My Cosplay has been featured here: https://www.youtube.com/watch?v=7oLIad409xo