I can't stress how important consistency is to any endeavor, whatever your age. This is particularly true when you are learning a new language. Practicing English everyday, whether it's 15 minutes a day or 4 hours (if you're seeking to achieve fluency within 3-4months), will make a difference that you'll notice right away and will encourage you to keep practicing! Here are a few tips to get you motivated:
1) Practice vocabulary: There are about 3,000 words in any language that are commonly used (more or less), so use flashcards to learn new words (you can learn about 30 everyday). Review these cards every day.
2) Practice reading. I recommend starting out with a good grammar book. Many of the most common mistakes for English learners are in conjugating verbs. If you want to advance beyond basic communication, you should know how to properly use the language. Practice reading everywhere you go (billboards, traffic signs, menus).
3) Practice speaking. Children are excellent learners of languages because they are not afraid to practice and to learn from their mistakes. You can't help but learn if you practice with a native speaker. Remember that everyone starts at the beginning, and that you are amazing for learning a second language!