To effectively sell shoes for cash online, consider the following strategies based on the provided sources:

1. Choose the Right Platform: Utilize popular online marketplaces such as Amazon, eBay, or specialized platforms like StockX and GOAT for selling designer or collectible sneakers. Each platform has its own audience and benefits, so select one that aligns with your shoe type and target market.

2. Set Up an Online Store: Create your own online store using platforms like Shopify or Ecwid. These services offer tools for building a professional-looking store, managing inventory, and processing payments securely.

3. Use Social Media and Niche Marketplaces: Leverage social media platforms like Instagram and Facebook to reach potential buyers directly. Also, consider niche marketplaces that cater specifically to shoe enthusiasts.

4. Optimize Listings: Provide detailed descriptions, set competitive prices, and use high-quality images to make your listings attractive. Authenticity proofs and condition reports can also help build trust with potential buyers.

5. Consider Fulfillment Services: If using platforms like Amazon, take advantage of fulfillment services to handle shipping and customer service, which can enhance buyer confidence and streamline operations.