Create your own vocabulary notebook. Every time you read, listen to or watch something, write down the words you don’t know, look them up in your dictionary and write down their meanings down your vocabulary notebook. Go back and look over your new words at least once a week. Try using your new words as much as you can when you speak and write English. This will help you remember your learned vocabulary.
Choose a few words from this list and write them down in your vocabulary notebook. If you are preparing for IELTS Academic, look at Avril Coxhead’s Academic word List and follow the same instructions.
Don’t forget that when you’re using new words, make sure you look at the different forms of the word, such as the noun and verb form. Learn how to use them correctly and practice using different forms in conversation and writing.
For example: I am contemplating (verb); the book is contemplative (adjective); Contemplation is important for study (noun).
Once you have a good foundation of words, you can progress to studying collocations and phrasal verbs to increase your range of vocabulary and expand how you use words in English conversation and writing.