used when the subject of the verb is "you" or the person being spoken to, and the object is the same person

Be careful with that knife or you'll cut yourself! 用那把刀要当心，否则你会弄伤自己的！

Katie, control yourself! 凯蒂，控制下自己！

used for emphasis when the subject is "you"

Did you make the dress yourself? 那件衣服是你自己做的吗？

You can do that yourself. 你可以自己做那件事。

to behave in your usual manner, rather than behaving in a way you think other people might like

The best thing you can do is to go into the interview and just be yourself. 你最明智的选择就是进去面试时自自然然地表现自己。

alone or without help from anyone else

I'm amazed you managed to move those boxes all by yourself. 你居然能一个人搬动那些箱子，真让我吃惊。

Do you like being by yourself sometimes or do you get lonely? 你喜欢有时候一个人独处，还是你会觉得孤单？

for your use only

So you have the whole house to yourself this weekend? 那么，本周末整个房子就是你一个人的天下了？

not to be, seem, or feel as happy or healthy as usual

Why don't you go home early if you're not feeling yourself? 你要是不太舒服的话，为什么不早些回家呢？

used when asking someone about their state of mind when they are physically ill

I know you must still be uncomfortable, but how are you in yourself? 我知道你肯定还是不舒服，不过你自己感觉怎么样？

used when both the subject and object of the verb are "you" and "you" is also being used to refer to people generally

You tell yourself everything's all right but you know it's not really. 你自己对自己说一切都好，但你知道事实并非如此。