Listening to the radio isn't going to magically make you bilingual, but it definitely helps! Especially if you find it interesting enough to keep doing. 🙂 You get to hear how people pronounce things and the specific words they choose in specific contexts. It may not seem like it's helping all that much, but it does improve your understanding. Same thing with music and movies. They're good ways to expand your vocabulary and get exposure to different accents and variations. It gives you more of a flavor for the actual living language. In all of my years of studying languages, before I switched careers, movies and music were my go-to methods for really delving into a language. I found that singing along to songs I liked really, really helped refine my pronunciation. It lets you do something repetitive without it seeming so boring, and even when we learn a song in our native language, we tend to imitate the singer, and that imitation helps you learn.
Reading can also be pretty useful, if you avoid some of the pitfalls. If you read to get a general idea of what's going on and then go back to look up a few words that seem really important to understanding, it'll be more enjoyable, and you'll read more than you would if your goal was to understand absolutely every word. I like reading the news and I like fiction, so those are two things that I used to read to practice. Worked pretty well.
Do see if you can find a speaking buddy somewhere, though. Writing is the most difficult skill to acquire, followed by speaking, so it's always super helpful to have a way to practice active skills instead of only passive ones like reading.
IME, Spanish has been pretty useful in my work in vet med, and it's saved our butts more than once. I've had to translate for the doctors before, and in a few instances, it would've been very difficult for them to communicate effectively otherwise. Simple phrases, gestures, etc. can take you a long way, but sometimes you're stuck. I think it's a great idea to work on practicing in another language. Keep at it. 🙂 And if I ever get around to making my sheet of English/Spanish medical terminology, I'll send it to you. 😀