Can somebody help me with some tips to dig for arrowheads? I live in Missouri and have property by a river.?

I find it very hard to dig for arrowheads, it’s hard work and my holes are very uncleanly dug. My family owns a good chunk of land out in Champion City, MO and the land is on both sides of the Bourbeuse River. There are 2 creeks on the property one starts up on a farmers field and acts like a channel that directs water right down to the river. I can tell the creek has been there hundreds of years because the bedrock is exposed and parts are eroded. The other creek starts on the opposite side of the property on our land and joins with other small creeks to form a larger creek about 10 ft wide. This creek runs a long way through the same farmer’s property all the way to another spot on the river.

Both of these creeks only get water in them when it rains so no fish live in them. I have only found 1 arrowhead on our property and it was in the first creek I described. I found it on March 19th, 2010. From the description and shape I have concluded that it is a Hemphill projectile point (The tip and one of the ears are broken off). Now, What I need some help with is, where I should start digging for points. Since I have found one, I know there have to be more under the soil. I need some tips on what to look for when I’m digging and where I should dig since there may have be a camp somewhere in the woods. What I would like to understand is where would be a good place to start looking for them? Since I live by a river I feel I have a better chance than other people to start unearthing artifacts. I figured that digging above the flood plain would be a better judgment than not, unless there were a race of aquatic Indians. The land that touches to the river has flood-plain then a steep wooded hill that stretches upwards at a good slope for 300-400 feet and then the land evens out into forest with several small creeks that only have water in them when it rains (I described them briefly above). Many people dig where they see “humps” along the ground where an ancient Indian house or camp may have been. Some say these humps are very small (only rise a few inches) but may be 5, 10, 20 or 30 feet across by a similar amount of feet wide. Where would I spot these humps? Would they be by the top of the ridge or more inland, perhaps even a good walk away from the river? If I do spot a hump, where should I dig at? Should I start in the center of the hump or start at the edge of the hump and work my way in?

I know I have typed a lot and it may be hard to understand but I feel someone who is good at digging for arrowheads may be able to help me.