I left the topic broad due to the fact that civilizations that have occupied the Americas have generally built one on top of the other when constructing their villages towns and citys. It is in these areas that I choose to hunt for treasure, not in sacred places or graveyards.  I will usually scout areas close to major sources of water, ie. creeks, streams and rivers. Lakes are not reliable many times due to so many being historically man made, what we're after are prehistoric artifacts. When it looks like I have found an acceptable water source, one that has survived the millenia, I will begin looking for my search sites. Search sites vary in kind, from receded creek or river banks, to plowed fields, and even rocky shelters high on the river's bluffs. When I have found acceptable search sites that I feel will produce artifacts, I will at this time seek to secure permission from the land owner to hunt. This can be the trickiest part of the whole process. Most people by nature do not want strangers bothering them, much less traipsing across their plowed farm land, you must be extremely diplomatic at this point, if you want to hunt. Tell the owner an interesting artifact story, offer to teach them to hunt, offer to share finds, but don't forget to just ask to hunt in the beginning. When you have secured your place to hunt and have checked all local, state, and federal laws for artifact hunting in the selected area, you are finally ready to hunt! I have found that when "surface hunting" for artifacts the best time to go is after a storm with pounding rains. You must allow the field to dry some so as not to disturb your farmers soil or damage a planted crop. Walk the length of plowed or planted rows and pay attention to glints of reflective flints or cherts and even shapes of crafted stones. Early Native American cultures produced most of their findable tools out of flints and cherts and you may find parts or even whole items turned up by the plow and washed by the rains. It is also possible to find early pottery shards and slate artifacts, as well as some made from a variety of materials. I have found a variety of artifacts in this way, including arrowheads that date up to 10,000 years before present. You may find a number of historic items in this same manner, including marbles, coins, jewelry, weapons, pipes, etc. I have found all of the afore mentioned items hunting in plowed fields next to a major water source. I have found over my many hunted fields that some areas of a field are productive and some are not. Unless you are familiar with the field you will have to hunt the entire field to find the areas that are productive, track and use this information to your advantage in future hunts. Hunt creek and river banks in this same manner, untill you can determine which areas to "Key" on each year. If you choose to hunt rock shelters you may as well bring your shovel and digging tools, as well as an artifact "shake screen" to hunt this area. The items you are looking for can be many feet below the current dirt level or may be just under the surface, so be carefull not to break the treasure you seek! Their are many books and clubs to help beginners with classifications and values of their finds, and trade shows and internet auction sites to buy and sell finds. You may also seek to have your artifact certified and papered by one of the experts in the field, this states, that a knowledgeable third party has examined and found the artifact to be genuine and may even state a condition grade, as well as a discription for a professional fee. I cannot emphasize enough, the part of my guide about "doing it right"  ...Get permission, know the laws, don't be a goul!  Most of all have fun and enjoy a hobby that is also profitable!