If I'm crying how do I stop.
Cry till its all out and u can't cry no more
You could try to blink faster or expose your eyes to sudden light. This will cause the pupils to constrict thus stopping the tears. You could also take in large gasps of air then breathe out.
Get over whatever you're crying about.
Just cry as how much you can so that u'll get rid of that memory.
Pray and find your peace about whatever is bothing u
Just start laughing or think of things that make you laugh. Do something silly. Eat tons of ice cream. Something like that.