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
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.
Play a Word Association Game
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.
Learn How to "Chunk"
Chunking is a popular memory device otherwise used to remember phone numbers, credit card numbers, social security numbers, etc. When it comes to strengthening vocabulary in a second language, you can use the same technique by chunking or chaining similar words together. For instance, make a cluster of all words that are somehow related to the the word "play." This would include verb variants, names of sports, terms related to jerseys, rules, and even numbers. When grouped together, the words will remain associated with each other in your mind. You can increase the efficiency of this method by focusing on one list or cluster every week. This way, the words will be segregated both by time gap and semantic similarity.
String a Story
If someone told you to remember the names of all the characters of a dozen novels, you will find it next to impossible to do so. However, if someone tells you the plot lines of the novels, the task will become considerably easier. People tend to remember names or characters by their unique attributes and the actions they perform. Therefore, always try to string a story out of the words you are supposed to study. Once you have made clusters, unleash your creativity and string a bizarre story out of these words. Say you have cluster of words relating to the verb "fight"' in Spanish including words like "luchar," "palear," "competir," make a story about "paleo"-lithic men having "lunch" after a fighting "competition." Since the sounds remain common, your mind can associate the words to their meanings quite easily. It can take some time and practice to apply these memory devices to a large number of words in a foreign language. However, it will become easier with time and you will be pleasantly surprised by the results. Good luck!