I advise you to spend 15 to 20 minutes daily listening to music and trying to catch a few words, once a week to watch a sitcom in order to learn new slangs - the comedy ones are the best for it.
Studying grammar in a daily basis (5-10 minutes) will also help you to get the main topics.
This way, in 6 months you`ll have a good vocabulary and will work your accent, the enough for chatting and traveling.
You`ll need another 6 months to get deeper into grammar and extra 6 to study text enrollment.
The key is to practice it daily. Eventual specific vocabulary will only be gathered as soon as you start interacting in English.