When choosing a blockchain platform for your NFT marketplace, several factors should be considered. Firstly, consider the scalability and transaction speed of the blockchain to ensure it can handle the volume of transactions expected on your marketplace. Additionally, evaluate the security features and consensus mechanism to safeguard digital assets and ensure trust among users. Furthermore, consider the developer community and available tools and resources for seamless integration and ongoing support. Lastly, assess the cost implications and compatibility with desired smart contract standards for NFT creation and trading.