The site looks good the ad placement, the template, and the color scheme is excellent however, I think it would be good to have some text at the top of the landing page to explain the purpose of the site.
Your site title needs to have keywords in it, not just the site name <title>Preview-central.com</title> The theme is also missing the meta description and the meta keywords. This is common in wordpress themes. But it needs to be fixed. Posting articles with the name of "admin" is not very professional. Change the posters name to something else. Did you mean to leave the default blog roll links in the right column? Shouldn't more important links go there? Do you have any friends that have sites you could link to? The header links - about, contact, search, amazon.com shop - the text colors fade into the background too much. Maybe change the colors of those links so they stand out a little more.
thanks @~kev~ i dont know so much about php and this is my first project with wordpress so i dont know how to change blog roll i try to remove that but cant find how about friends i dont have firends that have sites i will try to fix that all thanks again edit : i changed now poster name