One of the main differences is Litecoin has a shorter average block time of about 2.5 minutes, while Bitcoin's average block time is 10 minutes. This essentially means that transactions are sent on average every 2.5 minutes and 10 minutes respectively. Blocks, when mined, contain some of that currency to pay the miners, and that's how the crypto is mined.

Litecoin also uses the scrypt algorithm, as opposed to Bitcoin using SHA-256. Bitcoin is more suited for ASIC mining, while scrypt is generally very memory intensive, and normally better suited for GPU mining.