This process is called hardening off, because you are getting the plants ready for the harsher, outdoor conditions of wind and sun. I like to start by moving my plants out to my porch and deck for an hour or two each day. I extend this time a little every day until they are outside all of the time. It helps to get them accustomed to the same conditions they will face in the garden. A north facing porch will not prepare them for the intense sun of a south-facing garden.
Some people also use cold frames to harden off their plants and to extend their harvests.
These are wooden boxes with a window on top, and can be made from scrap wood and old windows easily. You stick the plants in their containers in the box, opening the window lid a little to vent the heat out. A great book to learn more about cold frames is The Four Season Harvest by Eliot Coleman. You can fence your garden in with vinyl-coating gardening fence that will last for years, or you can use chicken wire, or even nylon netting. The netting will keep the birds away because they don't like to get their feet caught in it.