I only two ways of obtaining somebody's sharingan: One: You can get it transplanted like Kakashi, he got his from Uchiha Obito in the Third Great Ninja War. Two: The second way is to take over a Uchiha's body by using the Living Corpse Reincarnation, however only Orochimaru is able to use it but it isn't always successful because Orochimaru tried this on Itachi and Sasuke and failed. Besides that I don't know any other methods of taking somebody's Sharingan, I would imagine that it is hard to get one from a Uchiha due to their vast amount of chakra and their sharingans.