To give you a general idea, for every 1000 views you get, you will receive 2 to 3 dollars. This is called the CPM and varies from person to person. To get 1000 views a day, you will have to write about 60 to 140 hubs, but that is definitely not an exact specification. So, if you get 1000 views a day, you will get about 30,000 a month which will mean $60 to $90 a month. However, it can take months or even years to reach this point, if you want to hit payout every month. But, if you want to see some earnings coming in, try writing 2 hubs every week, or take the 30 Hubs in 30 Days Challenge, this will boost your views and earnings.
I would recommend that you:
Write 2 hubs a week, and do some keyword research using the Google Keywords Tool, pick keywords with low competition and high searches.
It can take 6 to 9 months for hubs to 'mature'. Google likes older hubs so you will start seeing some decent search traffic in a few weeks to a few months.
I hope this answers your question! If you have any more just ask me!