let the punishment fit the crime!

I am guilty of always being quick to say "you're grounded forever!"...or whatever just pops out especially after I am worked up over the girls fighting or what not....I am working on being better at not letting it get to me and calmly applying a punishment...however I am finding it hard to find a corresponding punishment for the wrong committed!?!?!? hmmm...seems easy...but for me right now...it's not.