Buy an electronic dictionary or Word Tank. The key is to take it with you everywhere you go.
Whenever you hear or see a new word, put it in the memory. Then when you have some free time, on the train or waiting to pick the kids up from school, test yourself with the memory function.
The dictionary will flash up an English word at random, and you have to guess the meaning.
The best thing is that because you carry the electronic dictionary with you everywhere you go, you make emotional connections with the words.
For example when you see a word you think “Oh yes, that’ s the word that I heard at work last week” or “Oh yeah, I first heard that word at the end of year drinking party!”.
This way the words become your own.