Is there anything that bothers hers particularly: a newborn at home? day care? a familial problem that she has witnessed?
Be a good example to her and avoid shouting and using a loud voice.
Put words to her feelings so she learns to express them: "you are tired this is why you cry", "you are upset because I did not give you...".
1. Be firm with the child
2. Communicate well with him. Always explain to him why you have done so with him.
3. Be a good listener to him
4. Reward positively the good behavior.
5. You (as his father) and his mother should be united when dealing with any problem related to the child's behavior.
6. If he cries or screams, leave him until he calms down on his own.