Hi linkweb4u,
You are on the right path as far as using blogs to help with link building; however adding spam type links or comments is not really the way to go. Actually, they can hurt your sites rankings sometimes.
I suggest creating a blog or two on Blogger.com and writing current up to date content / articles on your industry or keywords related topics that you are trying to promote. After you have a few blog posts, search around the web and find similar industry related blogs and send them a link exchange email offer. Most bloggers are willing to exchange links and as your blog grows with content, traffic, and links; eventually others will contact you.
Now if you are looking for only one way links that is going to be a little more difficult. But it never hurts to ask and a lot of webmasters have multiple blogs and websites where they might be able to place your link on. Keep in mind you want quality inbound links that are placed in good locations on other related websites.
Hope this helps you to get going in the right direction.