The first thing you need to know is what you are looking for. Here are a few pictures of wild American ginseng plants in various stages of growth.
These photos are fairly typical of late July, late August, and late September where I live in Kentucky. Notice the leaf pattern, shape, size, edges. You will overlook many plants if you can't identify it by the leaves alone. People that just look for red berries or wait for it to turn yellow will not find as much.
First you need to find out when ginseng season starts in your state. In Kentucky it is August 15th. Next you need a place to go, something to dig the roots with, and something to put them in (any kind of sack or bag is fine really). Some people just like to use a flathead screwdriver. Some have "sang hoes" that they made themselves. I generally use one of the following.
Now to find some woods. If you don't have any suitable woods on your land or a friend, neighbor, or family member do not fret. You can get permits for most National Parks. You can also just simply ask someone for permission. Some will say no and some will say go ahead. Ideally the kind of woods we are looking for would be hardwood stands of poplar, maple, walnut, hickory and beech with around 70-80% shade. North-facing and East-facing slopes are best. The ground should be moist but well-drained. Now if it happens to be a dry year the ground may be dry nearly everywhere so if the other conditions are met, it still may be a good place.
Once you are in the woods, one way to tell if you are in a suitable spot is if you see some of the following wild plants: cohosh, goldenseal, trillium, jack-in-the-pulpit. You can find pictures of these by searching google images.
Just make sure you only harvest mature ginsing plants (three and four prongs) and plant the red berries back in the ground if they haven't fell off yet. When you dig a plant, first rake the leaves and debris away from it so you can see where the stalk enters the ground. Gently dig down around the stalk very carefully until you see the root. Usually you can see which way it is growing and then dig it up easier. If you are using a hoe type tool though you need to start digging away from the stalk and gently make your way back to the root and under it. If you happen to unearth a root that is quite small (say the size of a AAA battery for reference) or still young just plant it back. It should be 5 years or older before harvesting. You can count the bud scars to determine the age of the root. See below.
This should be enough to get you started. I'll put up an article tomorrow about what to do with your wild ginseng roots when you get home.
Click Here to see the best guide on Wild Ginseng.