Actually, it doesn't really matter what your first step is, just as long as you do something. You could...
- look up language classes in your local area
- find out whether studying in an English-speaking country is a possibility
- set up a new social networking account that you'll only use in English
- download a language learning app for your phone
- beg, buy or borrow a book in English to practise your reading
- start a blog
- try to meet English speakers socially to practise conversation
- do what you love - look for English videos, groups and sites relating to your hobbies and interests
And whatever you do, practise, practise, practise. Time, effort, and repetition will all help you to improve.
Congratulations! By taking that first step and finding a way to incorporate some more English into your daily life, you are already doing better at keeping your New Year's Resolution than most of the population! Now for the second step, and the third...