Collocations are 'semantically arbitrary restrictions which do not follow logically from the propositional meaning of a word' . Another way of looking at collocation would be to think of it in terms of the tendency of certain words to co-occur regularly in a given language.

  At one level, the tendency of certain words to co-occur has to do with their propositional meanings. For example, cheque is more likely to occur with bank, pay, money and write than with moon, butter, playground or repair. However, meaning cannot always account for collocational patterning. If it did, we might expect carry out , undertake or even perform to collocate with visit. Yet, English speakers typically pay a visit, less typically make a visit and are unlikely to perform a visit. We do not speak of grilling bread, even though we put it under the grill (Newman, 1988) . When butter and eggs go bad they are described in English as rancid and addled  respectively. Both rancid and addled mean rotten, but addled  butter and rancid eggs are unacceptable or at least unlikely collocations in English (Palmer , 1976). Moreover, words which we might think of  as synonyms or near-synonyms will often have quite different sets of collocates. English speakers typically break rules but they do not break regulations.

  When two words collocate, the relationship can hold between all or several of their various forms, combined in any grammatically acceptable order. For example, achieving aims, aims have been achieved , achievable aims, and the achievements of aims are all equally acceptable and typical in English. On other hand, it is often the case that words will collocate with other words in some of their forms but not in others. We bend rules in English but are unlikely to describe rules as unbendable. Instead, we usually talk of rules being inflexible.

  It seems that the patterns of collocation are largely arbitrary and independent of meaning. This is so both within and across languages. For example, the English verb deliver collocates with a number of nouns, for each of which Arabic uses a different verb. The Arabic " dictionary equivalent" of deliver is yusallim.
Arabic ..................................English
yusallimu kitaaban...............deliver a letter
yulqi khitaaban...............deliver a speech
yanqulu akhbaaran................deliver news
yawajjihu darbatan..............deliver a blow
yusdiru hukman.............deliver a verdict
yuwallidu imra'atan............deliver a baby

  The last Arabic expression, yuwallidu imra'atan , literally means something like ' deliver a woman ' or ' assist a woman in childbirth'. In the process of childbirth, Arabic focuses on the woman, whereas English prefers to focus on the baby; it would be unacceptable , under normal circumstances, to speak of delivering a woman in Modern English. This suggests that differences in collocational patterning among languages are not just a question of using a different verb with a given noun; they can involve totally different ways of portraying an event.
  Some collocations are in fact a direct reflection of the material, social , or moral environment in which they occur. This explain why bread collocates with butter in English but not in Arabic. Buy a house is a frequent collocation in English,, but in German it is very rare because the practice of house-buying is very different in the two cultures. Law and order is a common in English; in Arabic a more typical collocation would be al-qanuun wa al-taqaalid (law and convention/tradition).

Collocational range and collocational markedness
Every word in English can be said to have a range of items with which it is compatible. Range refers to the set of collocates, that is other words , which are typically associated with word in question. Two main factors can influence the collocational range of an item. The first is its level of specificity : the more general a word is , the broader its collocational range; the more specific it is , the more restricted its collocational range. The verb bury  is likely to have a much broader collocational range than any of its hyponyms, such as inter or entomb, for example. Only people can be interred , but you can bury people, a treasure, your head, face, feelings and memories The second factor which determines the collocational range of an item is the number of senses it has. Most words have several senses and they tend to attract a different set of collocates for each sense. For example, in its sense of ' manage' the verb run collocates with words like company, institution and business. In its sense of ' operate or provide' , it collocates with words like service and course.  

  A marked collocation is an unusual combination of words, one that challenges our expectations as hearers or readers. Marked collocations are often used in fiction, poetry, humour and advertisements. For example, some might say in an advertisement for getting your suitable match ' do you want to spice up your boring life? '
  To sum up, collocations are the tendency of certain words to co-occur regularly in a given language. They are created all the time by deliberately putting together words from different or opposing ranges.

References:
Baker, M. (1992) In Other Words  London : Routledge
Newman, A ( 1988) The Contrastive Analysis of Hebrew and English dress and cooking collocations
Palmer, F. R (1976) Semantics, Cambridge: Cambridge University Press.