While a significant part of learning a foreign language is conceptual, there are some things that you simply have to learn by heart, including new words. To build a strong vocabulary, you will need to rely on efficient memory devices. Contrary to popular belief, excellent memory is neither a genetic attribute, nor does it fall under the either-you-have-it-or-you-don't category. With the help of some innovative, out-of-the-box memory devices, you can increase your vocabulary by leaps and bounds.
The memory town method is a loose adaptation of the method of Loci, which was an extremely popular mnemonic technique among the ancient Greek civilization. Under this method, you need to establish a vocabulary-location blueprint in a town that you are familiar with. Recall a mental image of your town and segregate words according to the location. For instance, since nouns are the most commonly used words in any language, place them in your house at specific locations. Similarly, choose ornate and beautiful places like parks or museums for adjectives and sports clubs or offices for verbs, as these define activity. It also helps if you create specific distinctions in terms of gender-related words. Choose stereotypically feminine places like a salon for feminine nouns and masculine places like sports bars for masculine nouns. The trick is to somehow add life to words, to give them a character and find a place for them accordingly. Every time you need to remember a word, take this mental tour and extract the word you are looking for.
Remember playing the word association game when you were younger? It's time to use the same technique, albeit for more productive reasons. Break every word into sounds and link them to an image that relates the meaning of the word in your native language and the one you are trying to learn. This can get tricky sometimes but it's surprisingly effective. For instance, the Spanish word for a book is "libro." This is an easy one since books are kept in libraries and the Spanish word is "libro." Let's take a more complicated example - the Spanish verb "luchar" means "to fight." Think of a similar-sounding word like lunch or luncheon and imagine a fight between different dishes. Say, a loaf of bread is lashing out at your meatballs or something like that. Now, that's not an image you will forget easily, is it? Remember, the weirder it gets, the better for you.