Not sure what kind of servers you are using, but the important difference between mainnet and testnet is that we are working with real money in the mainnet, obviously.
So depending on what you did or didn’t do with your testnet servers, security is the main topic I’d focus on.
How to harden your servers, firewall config, ssh, using an air-gapped machine to sign transactions, how to use a hardware wallet, and so on.
Also, if your goal is to run a profitable stake pool, you should think about ways to promote your pool, think about a marketing strategy, your pool ‘brand’, your social media presence.
What are the prerequisites to be accepted as an ISPO (DEXes) or for IOG or CF delegation rounds.