how do i creditmaxx

i want to buy a house in about a year, so i want to have a good credit score to make the lenders like me . currently i have a score of 769 from one credit card through my bank with a limit of 1k USD, which i pay in full every month. what is the best way to increase my score over the course of a year? it seems like you're meant to have a bunch of different cards that you use a little bit from and then pay in full every month, but applying for a bunch of cards seems as though it'd lower my score. will one year of good payment history on new cards offset the loss?