Is it skill of ad placement, or raw traffic that drives clicks? If traffic, will you need a minimum (on average) amount before you start seeing good results in adsense revenue?
there is no hard and fast rule. however traffic definately improves your earnings. I suggest dont put adsense ads till you have enough traffic..at least 50-100 uniques per day.
I am averaging 300-400 uniques per day, but I have only made $14 in a few months of having a few adsense boxes up. I am finding the process of placing/converting this traffic very hard.
It depends on a numerous range of factors such as CTR, CPC. Unless you hit on to a very good niche, it would take substantial traffic.