I have benefitted a lot from the open exchange of information on WebmasterWorld. So, I guess I'll give a little back...
I was not happy with the conversion rate on one of my ecommerce sites, and wanted to identify
some of the conversion factors on my site. I set up some split tests, on one product page, to determine which factors were most important in generating conversions.
Originally, my site had a graphic buy button, which said Add to Cart, and had a small image of a shopping cart (155 pixels X 35pixels).
In my first test, I learned that the code button <input type="submit" name="add_to_cart" value="Buy Now!"> converted better than the graphic button,(33 conversions vs. 24) with the same number of page views.
I then set up a second split test, to isolate each variable-button text, type size, and button color.
I wanted to see which variables in the code button would give me the highest number of conversions, with the same number of page views.
Here are the conversions, by variable:
Buy Now!- 28 conversions
Place Secure Order-44 conversions
Add to Cart-30 conversions
Button Type Size:
Gray Default Button-22 conversions
Light Blue Button-40 conversions
Light Red Button- 40 conversions
A buy button with 'Place Secure Order', and light blue or light red background color will convert best. Type font size doesn't seem to matter much.
My optimal buy button:
<input type="submit" name="add_to_cart" value="Place Secure Order" style="background-color: #B0C4E9">
Hope this helps you as much as it has helped me.