I just divided a violet plant that I got from my mom. I gave one half to her and kept the other. I put the plant out on my windowsill and then after a few days I saw it was getting kinda brown and dried out, so I watered it and put it on a less sunny windowsill. I think I might have watered it too much, because a few days later, I found some mildew under the leaves and it pretty much looked like the picture. My mom's plant is fine.

I don't think I can save it, but do you guys have any tips to avoid this next time?