Crying children create anxiety for parents who just want the crying to stop. When the crying doesn't stop, parents often feel helpless, frustrated and may feel inclined to cry themselves. Rather than trying to get your child to stop crying, accept it. Understand that your child is communicating in the best way he knows how. By empathizing with (rather than trying to stifle) his emotions, your child will likely stop crying on his own.
Calm yourself. Children are extremely sensitive to the mood of their parents. If you're frustrated and annoyed by your child's emotions, your child can tell. This will make him cry harder. Remind yourself that crying has been your child's main method of communication since birth and he's only doing what comes naturally. If you want your child to control his emotions, you must first control yours.
Hold him. Children need physical reassurance. If your child is crying, give him a hug. Let him listen to your heart beat. Speak loving phrases in his ear like, "It's okay. I love you". Rub his back. Let your child know that your arms is a safe space to feel whatever he's feeling. Knowing that he can cry in your arms without negative repercussion will likely lessen the need.
Encourage him to use his words. Tell your child that mommy and daddy can meet his needs if you know what they are. Say, "Can you use your big boy words? Can you tell mommy and daddy what's wrong?" Ask questions. For example, "Do you want something? Are you hurt? Are you feeling sad? Are you angry?"
Empathize. Tell your child that its alright to feel whatever he's feeling. Explain that everyone (including you) feels sad/angry/afraid/upset sometimes. Tell him that you understand and that you know the feelings will pass. Your child might be tired of crying, just as you are tired of hearing him cry.
Cry with him. It's difficult emotionally when your child won't stop crying. If you feel like crying, do it. Take the cue from your child and let loose. Your child will likely be so shocked at your tears that he'll forget to cry in his rush to comfort you.
Be proactive. When your child is feeling happy, talk to him about his frequent crying. Ask him why he gets sad. Tell your child that he needs a happy thought -- it could be his friends, his favorite food or television show, or a happy memory. Explain that he needs to remember his happy thought when he's upset.