The first best thing a blog owner will wish is, to get his blog sponsored. If you have started a blog yesterday and come searching for sponsors, its very rare that some one will sponsor your blog because sponsors too want themselves to be promoted on reputed blogs. So this is a job of lil bit patience, experience and your networking capablity.

First thing you need to make sure is that your blog is fully "Ready". By the term "Ready" i mean is :
->Your blog should have enough posts.
->You should write quality posts.
->Older your blog better it is, Old is gold :).
->Good page rank, which depends mostly on your blog age, in other words i mean a blog will have better page rank if promoted for longer time. Also visitors build up as the blog is more older and is indexed efficiently by major search engines.

Where will you find the sponsors?
As i had mentioned before, your social network should be large enough (more friends on web). Be in touch with as many bloggers you find on blog communities like mybloglog.com and blogcatalog.com. Some will willingly tell you about the sponsors you need. Also you may come across sponsors directly, all you need to do is know what are their needs and are they related to your niche (topics you work or write on). Do not expect high paying sponsors in the begining, but as time prevails you can get good sponsors with your experience in this stream.

While surfing the web i came across a site that provided an interface between bloggers and sponsorers - Socialspark. Its a community where you can find not only sponsors for your blog but also find offers of writing a sponsored post on your blog.