I had exactly the same problem except mine was Chinese. Had a ok teacher, then had a awesome teacher except he didnt teach us but played pegs and cricket inside the classroom, with loads of classmate who just didn't care about Chinese but more of having fun. Most of the class quited when that teacher quited, and we had a awesome teacher who actually taught us stuff, made quizzes and jokes and stuff. Then next year, we had a crappy teacher again who just made us do work and not teaching us anything.

I guess the best way is to get your self in the situation that you have to use Spanish. Like going to Spain or staying in your Hispanic friends house over the holiday.

I heard that Spanish is mostly about learning lots of vocabs. I suggest learning a lot of them and watch Spanish news or something to practice the sound of it.

Hope that helps