Haters and enemies can be annoying and their insults will upset you. First, you need to find out why they hate you; you can ask them nicely and calmly. Still, do not approach your hater, if you know they are nasty and capable of hurting you or leaving you in embarrassment.
Some people can be given a chance to realize that they have nothing to hate you for and that you are not a bad person. Other people just do not like you, so do not waste your energy and time with them.
If you realize it is your fault that they hate you, be mature and apologize to them, and if they do not accept it, there is nothing more to do but to ignore them. When they need help, give them help because this will prove you are kind and friendly.
Treat your hater well so they respond in a reasonable way, if not, others will see that you have tried and will respect you for it. If you try to help your enemy and they are still hostile, then stop helping because this only gets them to take advantage of your kindness.
Your haters will probably insult you because they are jealous, so ignore whatever they say and remember they want you to react by saying something bad to you. Pretend you did not hear it and do not give them any attention, and after a few times of trying to bother you, they will get bored and stop doing it.
Keep in mind it is impossible to please all the people all the time. Surround yourself with people who like you for who you are to feel more confident about yourself; having your friends by your side will help you ignore your haters.