Nobody speaks Spanish at home. How can I practice on my own?

Vocab: Songs, TV, Films. To learn a word you have to see it, hear it and say it at least 5 times.
Grammar: Read. Why? Because the more you see grammar in use, the more you will reproduce it in writing and speaking.
Speaking: Talk to yourself! Thinking out loud improves fluency. The more exposure, the more you will do this.