Blogs help because it gives you tons of unique onsite content for Google to eat up. JUst make sure you don't put any dup content on there.
Write original, interesting content on your blog. Post every day. Make sure you are pinging it. Roberts Golden Rule of On Page Optimization is: Make the content and the apprearance of the blog, the best possible for human beings. Momentrily forget about SEO. Ensure that a real person will find it pleasing and useful. There is a ton of free info on the Net for On Page Optimization. Avail yourself of that. There are 19 essential factors for On Page Optimization. They are easy to do and entirely under your control (unless your site is a free blog). Hope this helps. Best success to you, Internetmarketing108
A blog extends your site's reach to myriad long tail keywords. The more content you create the more chance of more visitors you will have.