you should have consistent unique/different visitors ranging from 100-200/day for slow earnings 1000-2000/day for higher earnings!
try get as much as you can but as the others said 100 unique visitors a day is good but if you want to start earn money with adsense you need at least 1000 visitors a day
Not just traffic, but quality visitors. I always consider adsense as a scenario where "the more is not always the merrier" .
I've always been told that to make it worth your while to start with Adsense you should have 200 unique visitors per day.
If your site content is unique or your site is related to high paying keywords like insurance and forex and other and you have good traffic like 300 to 400 unique visitors daily you can easily earn 3 or 4 usd on daily basis.
I agree with @Milo Odin it depends on your CPC too, if you've got a good CPC 300 visits/day for good original and unique content is fantastic!
Yes, thats a difficult question to answer. Its a good idea to make sure your site is optimized for Adsense ad placement. Then start testing traffic sources using Adsense Channels. SEO, Articles & Backlink building are tasks you should be doing everyday to get things moving.
The more the traffic, the more the money you make online Making money online is all about getting traffic
more traffict, more earning adsense we can get, with high quality of content and strong backlink, we can get money from adsense growing up every day.
100 unique visitors will get 2 to 3 $ daily. To get approved by adsense, you will need quality content