I do hope that you have gone through the answer posted by other members above. Here I am with my one cent of words for your good.
Please note that 1000 visitors per month is not a good number to think of displaying ads on your blog or website. You can, for sure. But that would take years in just hoping to reach a minimum threshold when you can withdraw the amount you have earned.
If I were in your place, having a blog with 1000 visitors per month and with advertisers willing to show ads on it. I would have either dropped this idea, or may have offered the advertisers to bid an amount themselves.
For displaying advertisements on your blog or websites and actually make some money, you must get at least 1000 visitors on a daily basis and not in a month.
Personally, I do have a blog that has not been updated from quite a few years. It gets around 80k to 90k monthly visitors but not enough income to pay me monthly. It does make around 9 USD or such on a good day. Kindly take it as an example...
If you really have advertisers who are interested to display theirs ads on your blog, you should work on increasing traffic on your blog by adding more and regular content to it. And right when you reach around 1000 visitors per day limit, you can talk to your advertisers to show their ads on your blog unlimited time everyday by paying you a daily fee anywhere around 300 INR or 900 INR.
I can understand that it may not be a good amount, but that is all we can expect from a blog with just 1000 visitors per day.
I would advice you to concentrate only on adding more content to your blog on a regular basis, make long posts, short posts with considerable amount of related keywords and keep overall quality of your blog high. As and when the number of visitors to your blog with increase, you can always think of trying and implying news ways to monetize your blog.
And meanwhile, you must try to apply for an AdSense account for your blog. If they accept your blog, that is good. And if they will reject your application at this time, you will be given a solid reason why your application was rejected. These are generally related to the content or quality of your blog. This way, you can always rectify those errors and re-apply for AdSense in future. (A free, professional advice from AdSense team? Maybe)
"Your value does not decrease based on someone's inability to see your worth"