Memorize the most common meaning of a word that you find in a dictionary. Although many words have multiple meanings, the most common meaning is often used much more frequently than the others. Dictionaries list entries in order from most common to least common. Learn the first definition listed as it is more likely to be this meaning than others.
Write example sentences that help you remember the different meanings of the word. Keep them short and simple so you can memorize them. Use your example sentence as a reference to check how a word is being used.
Make a list of synonyms for the different definitions. For example, the word "race" could be replaced with the synonyms "competition" or "ethnic group," depending on the intended meaning. When you come across a word with multiple meanings and you are unsure which meaning is correct, replace the word in question with a synonym you have learned. If the sentence still makes sense, then you will know which definition is being used.
Look for symbolism if the concrete definition of the word does not make sense in context. Imagine what the object (thread, coat, finger) looks like and what it does. The word "head" has several symbolic meanings that have to do with being first, leading or going forward because the head is at the top of the body and houses the brain. A symbolic meaning of "head" is "leader" as in the phrase, "the head of the committee."