Learning 2 languages at once

Hello! So a bit of background. I started learning japanese around 2 years ago and stuck to it for around a year. I stopped because i also had to study spanish for my school and learning two languages at the same time felt a bit too much. But i really want to get back into learning japanese so i've decided to start again. Do you guys have any tips for learning 2 languages at once or things i should or shouldnt do? I definitely want to focus more on japanese since i actually enjoy it and i'm happy if i just get a passing grade in my spanish class. Thank you already for the help!