1.Be informed of the options you have just incase things dont goto plan. Better to be informed before hand than to make decisions when your mind isn't in the right place.
2. stay calm and listen to your body
3. Make sure everything at home is taken care of other children etc so you can focus on the situation at hand organise your plan of attack and have backup plans in place. Eg babysitters, contacts etc.
One thing is to have your camera packed and ready in your bag I had my bag packed and forgot to put in the camera as I went early may not be an essential things but one thing I wish i had with me instead of a crappy phone camera.