I am updating my blog regularly for the support and creating some backlinks to my website, but my blog do not have good ranking so I am suspicious that 'either there any use of the backlinks coming to my website from blog or just I am wasting time in updation of blog.
There is a great big beautiful world out there just the other side of the door.
Billions of pages indexed.
The real question becomes… do you understand your intended user and what are you offering them of value to make them want to visit your site and return again?
you also have to promote and link build your blog… its not that hard to gain good rankings and for blog since its updated regularly which is love by google…
Submit your blogs in Blog Directories and Bookmark it in order to get Page Rank.
It would be great if you can post the url of your blog to help you, to get rankings you must be linking from good neighbors…
ranking your blog takes some time so be patience. You need more good backlinks from other high authority sites to increase your rankings. 
Hi Phil333, the same problem me also facing. I am getting traffic from search engines like google. People are coming from google.com to see my blog. But checking my PR, a grey bar is showing with N/A. As I am not having PR, my perfect money ads not giving money for showing their ad. My friend is getting $20 per month from them.
I think its all about time and efforts. You are doing right thing by updating it regularly but make sure that your contents and all that should be rich and unique so that can be useful for gaining some visitors to the site as well traffic.
Be patient, your blog will get rank in next time, just make sure update with unique content and than build backlinks to your blog.
I think the only thing that is out of our control is the domain of the blog. It is a known fact that older and more established websites have better chance to get to the top. You may want to work on getting more backlinks as well.
Lots of keyword anchored dofollow backlinks, some good content, and plenty of patience is all you need.
First thing in blogging is your passion for your niche, if you are passionate more for your subject of interest and want to share and help other same minded people then don’t worry about anything else like back links, rankings, SEO and things. Make good friends on facebook, twitter, linkedin and just keep on doing good work and share with others. Over the time you will see positive results but as chimeara said, be patience. Everything takes time to grow accept poverty 
Takes time man. Rome wasn’t built in a day.
Keep in mind that you must continue to advertise your blog. Ranking a site is not an easy task, yet not impossible. Writing and distributing articles, updating your blog content, commenting on other blogs and forum posting, are just some of the things that can be done in order to rank a site or in your case, your blog. Remember to invest sometime doing a little bit of advertising, promotion or marketing, whichever way you want to call it.
My best advice is to sign up for some linkbuilding services Angelas or Paul backlink service.
It may be the keywords you are targeting if you are targeting any at all. If you are in a competitive niche your keywords may be really hard to rank for without a ton of backlinks.
You also need to remember that google takes time to index your backlinks.
You can check your backlinks in google webmaster and yahoo site explorer.
It will help if you provide more relevant info like:
What is your traffic like in a month? Unique Visitors? Page views? What do you use to check your site traffic? Google Analytics? Wordpress Stats? How old is your blog?
These are some information that will help us to answer your question.
Yeah, the age of the blog is really a big factor in getting top rankings. If you are updating it everyday, you can have enough contents for the spiders to take and crawl for contents.
I think with the thousand SEO plugins for wordpress, you should use this on your site rather than other site scripts.