Teaching Collocations

Well, I bought "English Collocations in Use"-Michael McCarthy & Felicity O'Dell (Cambridge University Pess) and I found the argument at the beginning of the book quite interesting.
The authors, answering the question "Why learn collocations?" provide us with the perfect answer for our students when asking the same:" They will help you to speak and write English in a more natural way".
What is this "natural way"? It makes the difference between using vocabulary in certain structural patterns and using vocabulary in a way that makes sense to any native English speaker.
For example, a common mistake my students make(when they want to say >looking at something quickly without looking at the details>)is the use of "He threw his eyes over the window"-which usually makes me see the poor guy plucking his eyes and throwing them over... when the correct way of saying this is "He cast/run his/an eye over..."
This particular mistake is caused mainly because my students translate word for word. And the examples are many...
But, if we keep explaining this to them and give them such examples, they will eventually understand the meaning of "natural English" and will try to look for collocations in the dictionaries (and they will give up the habit of picking up the first entry).
I recommend you to try this book because it has tips for using the dictionary, types of collocations, register information and collocation exercises grouped on topics.