Memorize the parts of speech. There are eight basic parts of speech: verbs, nouns, pronouns, adverbs, adjectives, prepositions, conjunctions and interjections. Since these are the building blocks of the English language, memorizing how each part functions, plus a few examples of each will give you an improved foundation in English. At a minimum, memorize the meaning of action verbs. A sentence can be formed using one action verb alone.
Practice constructing sentences. A sentence contains a subject and a verb. Put words together both in writing, and verbalize them to practice communicating. Try to write a short story. Read it aloud to a friend or tutor who has a strong knowledge of English.
Read. People learn how to write and speak properly by experiencing what writers have composed. Pick out sentences in the reading, and attempt to copy their structure. For example, if a sentence contains a noun, a linking verb and an adjective, then write your own sentence containing a noun, a linking verb and an adjective.
Immerse yourself in the language. Listen to music. Watch movies. Go somewhere where you will hear people speaking. The more your hear English and practice using it, the stronger your language skills will be.