There should only exist 20 Crypto Dev NFT's and each one of them should be unique.
User's should be able to mint only 1 NFT with one transaction.
Whitelisted users, should have a 5 min presale period before the actual sale where they are guaranteed 1 NFT per transaction.
There should be a website for your NFT Collection.
You should have completed the Whitelist dApp
http://nft-collection-d3vd00m.vercel.app/