Commit to learning the language. Learning a new language is always difficult. However if done with the right attitude and planning, it can be a fun and rewarding experience. It is essential to commit to a plan that can help you achieve your goals.
Learn the English alphabet. That is an essential first task of anyone attempting to learn the language.
Learn the most commonly used English words. A list can be found by a simple search on the Internet. Such a list should include greetings, verbs, adjectives, nouns, and pronouns. Commit these to memory as you will be using them a lot. These will also help you become familiar with the language.
Simultaneously with Step 3, work your way through an introductory English book published in Polish. This will provide an introduction to grammatical nuances, including sentence structure, tenses, verbs, etc.
Make it a habit to watch English language movies and shows (with Polish subtitles if you prefer) and listen to English songs. Pick shows, movies, and songs from an English-speaking country whose accent you are comfortable with.
Practice reading and writing as much as possible.
Use the Internet. It is an excellent way to learn English. A simple search on your preferred search engine will bring up dozens of resources to help you learn to write, read, and speak.
Find a friend who speaks English. Practice speaking with him as much as you can. Start with simple greetings and gradually increase the sophistication of the conversation. Focus on syllable placement and pronunciation nuances.
Consistently challenge yourself with new vocabulary words, more difficult conversation levels, further use of subtitles, recitation of lyrics, or reading aloud.