I have a blog as www.placementmantra.com but job is not much high paying niche so how can I more promote is and earn money?
I see you are already using google adsense. Did you try to use some CPA offers? You can also promote some products as an affiliate or sell advertising space on your blog.
Try to get involve in job forums, job help, and maybe contact a few well known and respect local business to post some of the jobs on to your site.
Join as many job forums as possible, add a signature link, post at least 5+ posts a day on each of them. The more you post, the more effective this will be. Work hard, you will build backlinks, and traffic for your site!