I highly recommend FastCommerce.com to anyone starting small business marketing.
Small business owners need a professional e-commerce alternative. FastCommerce.com is a low-cost, high powered e-commerce platform that is free for the first fifty products, and $29.95 for 2,000 products.
Shopping Cart Software in FastCommerce
Easy Google Analytics Integration
Your product catalog automatically submitted to Google Shopping.
If I would be the one who is going to design, develop and market eCommerce website I might have followed below points.
Web design which gets success on distribution of equal attention of users to all my main products and product categories.
A simple navigation for both users and search engine.
A good logo design for branding and forums or blog for communication with buyers and to hear their feedback on specific products.
More than one way of payment processing gateway not just Paypal.
Free and affordable shipping with the money back promise in 30 days without any deduction.
If possible provide money paying in installment if you are selling costly products.