Just 2 cent comment, and I've stated this for 10 years here....
Don't fool yourself into thinking your site is either your main marketing tool or your sales tool. You should have people ready to purchase from other marketing methods by the time they reach your site. It is a closing tool (get their commitment fast and easy).
The role of your site is to make the buying experience as pain-free as possible and to up sell other products/accessories/services for sale. I.e. tell them (or show them) what they're buying and why they should buy it from you. Then make that process as easy as possible.
The vast majority of cs-cart merchants are never going to compete with Amazon so you better figure out what makes you different to your customers if you sell the same products. The customer should be ready to buy when they hit your site. You are never going to become the premier online shopping experience, so focus on getting the customer fulfilled in as few clicks as possible without overwhelming them with information.
Look at your own buying habits. How do you find what you're looking for? What makes you buy from example.com versus otherexample.com? Do you know anything about who you're buying from? Or are you judging the book by its cover? Once customers are at your site, can you incent them in any way to buy more products/services than they intended? (promotions, discounts, free-shipping, BOGO, etc.). Can you offer them any incentive during checkout summary to return to your site and buy from you again?
Marketing priorities are generally (product/service dependent):
1) Word of mouth
2) Organic search
3) Email marketing
4) Shopping aggregators
Customers are most sensitive to (decreasing priority)
1) total cost including shipping
2) product cost
3) shipping cost
4) Any response from any customer service request
5) Assumptions about customer service including return policies, etc.
6) Ease of navigation on the site
7) Ease of checkout (clarity, double-entry, automation, payment methods)
8) Impression of site security
Other than that, it's all easy! :-)