What I tend do is look at other sites which are competitors, so in the case of say a speaker company, look at KEF, Mission etc, what are their strengths and weaknesses? If a site works then you can copy for layout do a certain degree, but not rip it off.
One of my modules was all about design I learn't a lot about typograthy and graphic designs, one of the main conlcusions from it was to look at other print material/websites and see what works.
The main problem with graphics is you need creativity, I know Photoshop inside and out, but I lack the creativity to create a masterpeice.
Also don't treat a website as a print material. One of the biggest mistake graphics developers and web designers make is they think a designing a website is the same as designing a moster so you end up with this:
As a poster this is fine
http://www.5thavenuemanchester.com/
As a website it has loads of fundemental problems, basicialy if I was to carry out some usability engineering on it I would probably give it a very low usability score, it has too much graphics, things which should be text is done in graphics, so blind people have no chance of reading the website.
One of the points of the world wide web is its multimedia, by this I mean you can seperate text elements from graphics, with CSS you can design posters.
This might give you an idea, my boss designed the template but I developed most of the site, this is a classic example of a CSS poster I made
http://www.manchesterfa.co.uk/pswc/news/news012.htm
Annoying it is not displaying properly now, but its been edited by the client since I have produced it.
So its perfectly ok to use graphics as longs as its done properly. A blind person can listen to that poste so they get most the information a sighted person can see.