Can I get free blogs and put them on my site ? Am ...

Yes, search for article databases, you can publish any posts from those onto your site.  However, traffic you'll receive will be negligible from publishing other people's content onto your site.  Google will already have seen the article elsewhere and, in most cases, consider it duplicate content, putting your page into it's supplemental index.

It's best to write original, unique content, or ask others to write it for you.  Most people want to be paid for such work, but many will write in exchange for a link. 

You can then devise a keyword strategy, and focus your articles on keywords you want to boost in Google - just boosting those you think will bring in the traffic.

Source: myself @ Nottingham SEO Service

Try visiting some of these pages to teach you more about SEO, blogging and unique content:

SEOMoz:

Why Should a Search Engine Rank Your Site Above All the Others in its Field?

If you cannot answer this question clearly and precisely, the task of ranking higher will be exponentially more difficult. Search engines attempt to rank the very best sites with the most relevant content first in their results, and until your site's content is the best in its field, you will always struggle against the engines rather than bringing them to your doorstep.

It is in content quality that a site's true potential shows through, and although search engines cannot measure the likelihood that users will enjoy a site, the vote via links system operates as a proxy for identifying the best content in a market. With great content, therefore, come great links and, ultimately, high rankings. Deliver the content that users need, and the search engines will reward your site.

Content quality, however, like professional design, is not always dictated by strict rules and guidelines. What passes for "best of class" in one sector may be below average in another market. The competitiveness and interests of your peers and competitors in a space often determine what kind of content is necessary to rank. Despite these variances, however, several guidelines can be almost universally applied to produce content that is worthy of attention:

• Research Your Field
  Get out into the forums, blogs, and communities where folks in your industry spend their online discussion time. Note the most frequently asked questions, the most up-to-date topics, and the posts or headlines that generate the most interest. Apply this knowledge when you create high-quality content and directly address your market's needs. If 10,000 people in the botany field are seeking articles that contain more illustrated diagrams instead of just photos, delivering that piece can set your content (and your site) apart from the competition.

• Consult and Publish in Partnership with Industry Experts
  In any industry, there will be high-level, publically prominent experts as well as a second tier of "well-known in web circles" folks. Targeting either of these groups for collaborative efforts in publishing articles, reviewing your work or contributing (even via a few small quotes) can be immensely valuable. In this manner, you can be assured that your content is both link and visitor-worthy. In addition, when partnering with "experts", exposure methods are built-in, creating natural promotion angles.

• Create Documents that Can Serve as One-Stop Resources
  If you can provide a single article or resource that provides every aspect of what a potential visitor or searcher might be seeking, your chances for success in SEO go up. An "all-in-one" resource can provide more opportunities than a single subject resource in many cases. Don't be too broad as you attempt to execute this kind of content creation - it's still important to keep a narrow focus when you create your piece. The best balance can be found by putting yourself in the potential users' shoes - if your piece fits their needs and covers every side of their possible interests while remaining "on-message," you're ready to proceed.

• Provide Unique Information
  Make sure that when you design your content outline, you include data and information that can be found nowhere else. While collecting and amalgamating information across the web can create good content, it is the unique elements in your work that will be noticed and recommended.

• Serve Important Content in a Non-Commercial Format
  Creating a document format that is non-commercial is of exceptional importance for attracting links and attention. The communities of web and content builders are particularly attuned to the commercialization of the web and will consciously and sub-consciously link to and recommend resources that don't serve prominent or interfering advertising. If you must post ads, do so as subtlety and unobtrusively as possible.

• One Great Page is Worth a Thousand Good Pages
  While hundreds or dozens of on-topic pages that cover sections of an industry are valuable to a website's growth, it is actually far better to invest a significant amount of time and energy producing a few articles/resources of truly exceptional quality. To create documents that become "industry standard" on the web and are pointed to time after time as the "source" for further investigations, claims, documents, etc. is to truly succeed in the rankings battle. The value of "owning" this traffic and link source far outweighs a myriad of articles that are rarely read or linked to.