Don't use shiny colorful buttons on a website.And avoid using full background images, I'd recommend a simple patern instead. Using that much fancy stuff will just make it look unprofessional. Simple buttons and 2 colors only(excluding black and white).

Here's what I mean:
Good:
http://www.zu.com/html/

Bad:
http://www.sixtiespress.co.uk/

I'd recommend building your website in photoshop first and perfect it before you write the CSS.
Also, about the background image, make sure that isn't copywrited, cause that can get you into serious financial trouble.