I cry and yell and lose my temper pretty often. I'm human and I have emotions . Fortunately, I don't often threaten or punish (or threaten to punish) so I'm not using my power over my daughter at the same time that I'm loosing my temper.
I think saying "I'm sorry" is the most important first step. I try to do it promptly, to her face and at her level (ie: on the floor if she's throwing a fit on the rug). I then explain why I blew up-- just the final trigger not rehashing why we're in a fight-- but I do tell her how it made me feel. We hug and I let her cry and tell me why what I did bothered her. I agree that I acted like a toad. But, I then explain why what she was doing made me so mad. Usually we both cry and then we find a way to make up... a compromise using the timer is a common solution, or just a restart (this morning we decided to start the day over, for example) or we go and change the scenery.
For better or worse, I never leave a fight alone. I insist on working it out before moving on.