As a liquidity provider, you earn BAL by providing liquidity for approved tokens. It is easy to get a token approved; the approval process is in place to block malicious and non-standardized tokens from gaming the distribution system or abusing liquidity providers.
BAL is earned on a weekly basis based on snapshots throughout the week. At the time of writing, BAL is airdropped to eligible wallets at 2300UTC on Tuesdays, but the system will be updated in the very near future.
To get a token added to the BAL earning whitelist, swing by the #token-requests channel on our Discord (https://discord.com/invite/ARJWaeF). To streamline things, come armed with coingecko and etherscan links for the token contract. Example: