I just read a book called No More Morning Sickness that had a lot of great ideas in it. I miscarried earlier this year at 15 weeks, and I suffered horrible morning sickness, so I'm trying to learn all I can beforehand before I get pregnant again to see if I can ward it off.
The main theme of the book is to think about all the different kinds of foods and picture eating foods until you find one that won't make you sick. You don't have to be as worried about nutrician in your first trimester. If you ate well before your pregnancy, you have stores of nutrients already in your body, and most of the fetal development takes place in the last 2 trimesters anyway. Plus, for many women, if they can think of something that will stop the nausea, it will make them feel good enough that they can eat healthy food after that.
The kinds of things you should think about when picking a food are characteristics, e.g., hot or cold, sweet or sour, salty or bland, smooth or crunchy, etc. Reading the book will give you ideas of foods in each categories and some real life stories of things some women have found to help. When I was pregnant, crackers made me want to hurl. They stuck to my mouth and made me feel horrible. I did better with fruit, popsicles, and juicy things. Root beer also helped, but make sure you get a brand without caffiene.
I just wanted to throw in a couple of other thoughts.
