how can i continue to learn japanese outside of school?

i did japanese at school from year 7-12 and now i’m done i really want to keep it up, i have some japanese friends and eventually want to travel to japan and i worry now im finished school ill lose it, pluss i want to still improve! i find with me downloading any apps they all start with the basics which i already know. ive never really learnt a language outside of my class so any tips on how to study japanese as somone who’s already at a kind of intermediate level