When someone is being hateful, and they KNOW it, call them on it in a direct, but not hurtful way. I do it in a joking manner. I refuse to let someone disrespect me, or my family, but I don't want to handle it in a way that will escalate into something out of control. Most times these people will see that you will "fight back", and will leave you alone.
Never allow someone to get the best out of you, to where you feel bad afterwards.
And then there are the times that you need to let the stupid remarks, from unintelligent people, just go.
You just need to learn the difference between the two.
In the end, you need to forgive and forget.