How to teach vocabulary

Professor Jeremy Harmer reports that words are quite important. And why are them so important? Words are what a language is made of, their meanings, how they relate to each other. He says that we have a magic ability to twist their meanings sometimes and it make the language very fun. It's true. The more knowledge we have in this field, the easiest way to communicate ourselves, bigger is the possibility to make people to understand us. How to improve our range of vocabulary? There are many books focusing this subject, but according to Harmer vocabulary is more than merely lists. Meanings sometimes can change if our intention is to use it metaphorically, how they can be form, changing a noun to a verb, for example.
He believes that perhaps the best vocabulary exercises are reading and listening.
Students can learn vocabulary from many ways : by showing objects or pictures, listing a number of things in categories such as fruit, furniture, clothing, vegetable, by matching words with definition, through music and so on.
Harmer also point out that apart from teaching vocabulary, teachers should also help students to acquire vocabulary related skills, such as dictionary use and guessing strategies. I agree with him and I consider these points very important.