1. Use the new word in a sentence
After you have read the word and understood its meaning, use that new word in your own sentence. It is best to try and create a sentence that has some type of relationship or connection with your life.
2. Look for grammatical variations of the word
Look for the different ways (grammatical forms) the word can appear. For example if the word to suspect (a verb) is given to you, you can look for its noun form (suspicion), its adjective form (suspicious) etc. Suspect can also be a noun (a suspect). Remember that not all words have all grammatical forms. It pays to have a good English dictionary to help you with this.
Once you have the different forms of the new word, you can then try and make a sentence with each one.
3. Do Word Associations
Try and associate the word with other things (like a mind map). Not only will it help you remember the new word but it will also increase your knowledge (vocabulary) of other things associated with the word.
For example if you have the new word CAR (a noun),
Think of nouns associated with the word (parts of a car: windscreen, steering wheel…)
Think of verbs associated with the word (to Brake, to accelerate, to crash…)
Think of adjectives to describe it (Fast, rusty… )
Think of examples of the word (Limousine, Jeep…)
If the word is an adjective for example BIG
Think of synonyms or words with a similar meaning (large, enormous, huge…)
Think of antonyms or opposites (small, tiny…)
Think of examples of the adjective (Big: Elephant, a continent, Jupiter…)
4. Carry a list or a notepad with you
Write the new word and its meaning (and maybe an example too) in a small notepad that you can carry with you and read whenever you have a spare moment (or some people keep them in their smartphone). This can be read while you are sitting on a bus, on the underground/subway, or while you are in a waiting room. This will help you see the words more than once and will help them stick in your mind.