Watch movies with subtitles.
Read and look up words you don't know.
Write definitions in English and your first language.
Make a vocabulary quiz.
Use your own words to make sentences.
Read the newspaper.
Use a word of the day app.
Look...write...speak
Read a novel multiple times.
Don't be afraid to use the new word outside.
Write in a journal.
How many of these strategies have you tried?
What other tips do you have?