First, what are collocations? Collocations are sets of words that are used commonly together. It is said that knowing collocations helps you sound more natural. While to an extent that is true, your time is not going to be well-spent memorizing hundreds or thousands of collocations (there are plenty of lists of these). But there are cases when they are useful!
Collocations are only truly useful in these cases: 1. When the words used are different from your native language. Example: "Tengo hambre" translates directly to I have hunger, but you would naturally say, "I am hungry" in English. 2. When the words used in your native language translate to a synonym of the more natural word (a bit "false friend"-like). This is a bit similar to #1. For example: "construir una sociedad" translates directly to "construct a society," but more naturally you would say "build a society" in English. 3. When your native language has one word that translates to multiple words in English. Example: hacer translates to do and make, por translates to for and by, para translates to for and to, en translates to on and in. 4. The instances when English uses multiple words for stating the same thing. For example: I will make cookies in August on Tuesday the 4th at 5 PM. I'll turn in my paper by Wednesday at 3 PM. In, On, At, and By are all used for stating a time! Ask me about when to use these in class! 5. When words in English have a similar, but slightly different meaning like over and on. 6. When the same word is used slightly differently from the use in your native language. For example: In both English and Spanish, food can be rich (rico). In Spanish any food can be rico so long as it is tasty, but in English only food that is high in things like sugar, oil, butter, cream etc, that you cannot eat too much of or are satisfied by eating little. For example, that cheesecake was so rich, I could only eat two bites of it, but boy, it was delicious! Rich can also be used in a negative context: I couldn't eat much of that dessert, it was too rich. Please let me know of any other examples, especially with native languages aside from Spanish! As an English teacher I want to continue building my list of the most useful collocations for my students! I am all about being sure you progress in the most efficient manner possible.