I think the "Quality Photos" tip is the best. For certain products, allowing customers to submit photos is also great (think Threadless.com style) since it's both product shots and social proof.
Its mostly meat and potatoes stuff. (Which I somehow managed to ever avoid doing in three years. Amazing what a fresh look helps you discover.)
http://www.kalzumeus.com/2009/07/26/practical-conversion-tip...
Have you tried chat and/or click-to-call solutions like liveperson's or eStara's? What's your opinion on these services? (even if you haven't tried them)
I have found that many articles talk about analyzing and optimizing cpc and cpm campaigns which is great for bigger sites with phenomenal traffic and online exposure. However, for small boutiques like Izola, I have found that these 3 tips have the highest value (income/time) ratio.