When choosing an search engine optimization service provider for a small e-commerce business, several key factors must be considered. First, assess their experience and expertise in e-commerce SEO, as it requires specific strategies. Check their portfolio to see if they've worked with similar businesses. Additionally, ask for references or case studies. Transparency, clear communication, and a results-oriented approach are also crucial. Ensure they provide detailed reports on progress. Pricing should be competitive and within your budget. Lastly, examine their knowledge of the latest SEO trends and algorithms, as staying up-to-date is vital for e-commerce success.