Be Mentally and Emotionally Strong

Do you hate it when someone puts you down, and then just walks away, leaving you hanging? Do you always give in to EVERYTHING people tell you to do? Are you a doormat? or do you just feel weak inside? well, not anymore:
When someone says an offense to you, try tensing your muscles. This makes you feel physically strong, thus giving the mental affect that you are strong.
Strip yourself of your emotions, when you feel close to tears or punching someone, you will not have them with you to give you that extra push. (You could try clearing your mind of the thought, and make a distraction)
If you are funny, when they say something, give witty or (possibly) pointless come-backs which will leave THEM hanging on a thread, maybe a bit confused?
Laugh it off.
If you are one of those people who tends to ACTUALLY punch people, then imagine your wrist is chained to your side, and instead of physically punching them, do it in your head.
Do the opposite of what your emotions are telling you to think, therefore making you more in control, and pushing you away from the edge of insanity.
If you are on the verge of starting a fight, imagine how you'd feel if it was done to you. It's obvious you'd rather NOT have your nose bleeding, or something similar.
When you accidentally stub your toe or something, draw in a lungful of air, then hold it until the pain is gone. Or, instead of holding it, let it out slowly.

Always test these methods out on the person who made you look at this page in the first place, because your emotions won't be fooled if your friend is helping you.
try thinking of your eyes as vacuums, pulling the tears back if you do start crying, and it ACTUALLY WORKS!!!
If you still knock people around, get help. that's not insecurity, that's bullying!

This may not work every time. Remember, practice makes perfect!
Don't use these methods on children, if you're an adult. They may not understand, and it could upset them.