1. Stay calm.
Never react in anger or blow your stack. If you're so POd that you can't trust yourself to be calm, then go away and come back when you can. The workplace is no place for that kind of behavior, period.
2. Attack the problem, not the person.
When you criticize or attack someone personally, you risk burning a bridge. Focus on the real issues at hand. You know, what the company actually pays you to do.
3. Be open and honest.
The second you grit your teeth, cross your arms, and close your mind, you give in to stubborn childish behavior. But if you remain open and keep your wits about you, you'll manage to do the right thing in a tough situation.
4. Don't lose perspective.
Try to remember that you're being paid to do a job, not to fight a war. The workplace is about business. You know, customers, products, that sort of thing. It's not about you … or him.
5. Try to be empathetic.
Put yourself in other shoes and try to understand her perspective. If you can't or you're not sure what it is, then ask; you're assumptions may be wrong. If she does the same, next thing you know, you have detente.
6. Take the high road.
That doesn't mean be quiet when something needs to be said. It means say it at a time and place and in a manner that's reasonable and respectful of all present. If you kick yourself afterwards, then you probably didn't do it right.
7. Have faith in yourself.
The workplace is no place for yes-men. You were hired for a reason, and it's not to blindly march along with the pack. If that's what management wants, you work for a crappy company.