How can I increase my true retention ?

Im in medical school and I use FSRS from the beginning of the year, I first set up my retention goal to 90% as I read on internet, my true retention was 77,9 %. Now I increase it with the goal to achieve more true retention, I am 93% rn and I am at 79,6% true retention. I would like to know what to do in order to be able to know better my cards if possible. Thank's for your answers