As for my personal experience is concerned, memorizing words from a book or a wordlist is totally rubbish. For me, the best way is to enhance someone's vocabulary is to hit the books daily and once they come across some sophisticated words, just try to jot them down on a sheet of paper and then look them in a good dictionary. Re-read the same page again. Otherwise, they can look them up as they come across. The big question is still unanswered how do they remember them.
I create myself a method perhaps you people already knew that.
a) Taka a piece of paper and cut down into 4 equal rectangle bits.
b) Take a bit, On one side, you have to write a complete definition from a cambridge dictionary or any other good dictionaries.
c) On the other side, you have to write a couple of sentences in order to know how to use a word exactly. Plus word's name and its nature.
d) Make as many word cards as you wish. They are easy to make.
e) Read the definition and guess the word, once you guess the word quickly and read the example sentences and do not try to include it in the next repetition's - try to repeat it after 3 days and then add up to same days as you judge words quickly.
f) on the other hand, you do not guess the word, try to include it in next repetition.
g) more importantly, they are portable you can do at any time or at anywhere.
I show an example for you:
Q: A gas or substance is poisonous or very harmful ( you read it and guess the word)
A: Noxious you can write whether word is 'v' or 'adj' ..etc)
Many household products give off noxious fumes
the heavy, noxious smell of burning sugar, butter, fats and flour