Congrats Wakizashi-sama !

1st Get Healthy. Your partner will have to eat healthy so start right now in doing the same. You will also need to be fit when the baby is born. The first 6 weeks as a newborn is hell on the parents you will suffer from sleep depravation, you will be very very tired, you will need to be as fit as you can to deal with everything.

2nd A little knowledge goes a long way. Learn about what you can do for your partner and the child. It will remove some of the worries from yourself, make you feel more confident, and if you are seen to be learning about it your partner will feel more confident in you too.

3rd Enjoy it. Really. They are the timetable. So for now lavish attention on your partner, go to the movies (you won't be able to for some time after the child is born), do things as a couple. When the child is born you are going to have some very tough times, simply put the child first, enjoy the small moments and things will eventually fall into place.

4th Ask Idaho-sama, he survived twins.