Should be an expert at promoting ecommerce businesses organically as well as through paid marketing.
Communication and Coordination skills will be a must since you would be interacting with clients in most cases.
Should be proficient with tools for:
• Google & Facebook ads
• Google Analytics & Search Console
• Google Tag Manager
• Google Shopping Feed
If you are familiar with Conversion Rate Optimization techniques as mentioned below it would be an added advantage, this would be to analyze results and identify successes, failures, and trends.