Teaching English, no matter how long you’ve learned it or taught it, and it’s been many years now, is never easy for the non-native. Teaching students who have already acquired an intermediate level of English one faces questions like ‘Can you say ‘poor diet’?’ or ‘Is it possible to say ‘malnourished’ instead of ‘undernourished’ in exercise 4?’ These are not easy to answer since, either you have learnt the examples yourself or you have to look them up. We lack the “internal” grammar and dictionaries only the native speakers of a language can use to find the appropriate answer.
I have been looking for accessible information dealing with collocations in English and have come across this site, which really impressed me. Be sure to have a look at it if you need clear explanations and good examples of interesting grammar and vocabulary points.