There are many things I know about now that I wish I had known before I got pregnant.
The first is a book called 'The Yummy Mummy Pregnancy Cookbook'. I got a copy of this recently from a library sale (a great way to pick up cheap books - I'm lucky in that my Mum works at a library so I get first choice!)
It provides helpful advice for pregnancy nutrition (including foods to get you through morning sickness), maintaining a healthy weight and recipes that I still use now. I thoroughly recommend it.