That blogspot link is a great one. Many many people I know have followed that through to great success.
There will be many pros on here who can give great advice, but I was in the same place as you last summer and wanted to photograph a piece of hifi I designed, so here are some basics I used.
One basic thing you might be missing is sync speed.
Most flashes work best with a shutter speed of something between 1/250-300th so go into Manual mode, set the shutter to that
Then choose a aperture that gives the required depth of field. For product photography you may want an f-number greater than f11.
Start with a low iso – My Canon seems to like ISO160
Take a photo, view the histogram and adjust flash brightness/closeness until exposure is good.
If you’re at max brightness, then you can widen aperture, or increase ISO depending on the compromise you want to make.
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I think the main thing for me has been softening the quality of light and bouncing the flash off reflectors, lightboxes, etc in order to partially fill shadows. I also ended up with 2 cheap yongnuo flashes to do this job.
My first results are here:
http://www.luminmusic.com/lumin-s1.html (gallery is halfway down the page)
Ideally, for this kind of job you wouldn’t use flashes at all – fixed lights would make life 10x easier.