The moment your Adsense is approved, you can begin earning money but only if people are clicking your ads.
The best advice I could give is to keep building up your content so you get more people that CAN view your ads; it's not a guarantee that they'll click them but you'll have a greater chance when you play the numbers.
From what I've seen, you generally get between 2 - 6% click through with Adsense (and that's on the high side) - this is coming from experience with my own websites.
So, you could (generally) expect 2 people to click an ad per 100 people that visit your page. Multiply that by a few thousands it will go up (obviously) but don't forget that not all ads pay well because you only get about 60% of the adsense revenue (other half goes to Google).