1. Gain lots of weight so she feels better about getting fat. Either that or lose any extra weight you may have and get really muscular. Ask her which she prefers.
2. Shower once every 2 hours. After each shower, apply liberal amounts of unscented deoderant to your armpits AND feet. Then brush your teeth for 10 minutes straight.
3. Massage her entire body from shoulders to feet nightly. But do not expect it to lead to anything sexual.
4. When she throws up, bring her crackers and water. Do not, under any circumstances, say "Ew."
5. Whenever you notice her looking in the mirror, tell her she looks like a glowing pregnant goddess.
6. Read every parenting book she reads and casually mention facts that you've learned.
7. Do romantic things like bring her flowers, take her out on dates, clean the house, and run to Taco Bell at midnight when she has a craving for tacos.
8. If she curses / hits you / yells at you, etc. just remember that this is half your fault and she has to do 100% of the suffering. That's her only way of sharing the suffering with you. It's really a nice gesture if you think about it, because now you can feel more involved.
9. Go to every single prenatal appointment. Shed a tear when you see the ultrasound. Get extremely excited no matter what the gender is. Oh and act interested whenever she brings up baby names, even if that is every single night.
10. Basically, whatever she wants, do it. Even if it makes absolutely no sense to you. If you follow all of these rules, you may receive a special reward in bed at the end of the day. Just be aware that the reward may be waiting for the baby to kick for a half an hour, stroking your wife's hair as she weeps and talks in depth about the miracle of life for an hour, then falls asleep while snoring in your ear.