The evil witch's survival plan is a Manga/Manhwa/Manhua in english language, Manhua series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

The daughter of a well-known family, Xiao Yao, died of a serious illness, upon awakening she discovered that she had become Abella, the evil sister of the heroine of "The Imperial Knight fell in love with me." As a princess, she didn't possess magic, and under her father's repeated indulgence, her personality grew arrogant and stubborn. She causing quite a bit of trouble, in the end, for the throne, she kills her father and her sister, and ends up in ruin. Xiao Yao then decided to save people, but found that the development of the story seems to have some small changes...