Stop eating animal products. Ha.
I recommend getting hold of a copy of Becoming Vegan which contains chapters on all the important nutrients, including why we need them and where you can get them (sans meat and dairy), plus loads of info on becoming vegan in general, such as the history and how it benefits practically everyone.
I also recommend getting hold of a copy of Vegan With a Vengeance, because I have it and because it contains the recipe for the tastiest stew in the world. All the recipes can be treated as a starting point to add your own twists to – I don’t think I’ve made anything in it to the correct recipe but it’s all been delicious.
My experience turning vegan is charted here. Here’s a page of other links on how to become vegan.
I have a links page full of internet vegans from whom you can learn much.
If you experience trouble or inconvenience, don’t give in. I don’t think there are any vegan police yet, so go at your own pace in reducing animal consumption.