(My answer to this question at Quora.com)
As Adam Booth has indicated, the word of is often indicated by a modification of the word’s ending.
Thus, the word ‘people’ is anashim, and ‘village’ is kfar, but to say ‘people of the village’ you would typically avoid saying anashim shel hakfar in favour of anshei hakfar — the ending ei (pron. ay) signifying plural + of.
Similarly birkat hamazon is a shorter and much preferred way of saying ‘the blessing of the food’ than habrakhah shel hamazon.
Finally, it should be noted that the word shel is a comparatively late innovation: it doesn’t appear in the Bible, but came about during the Talmud as a contraction of she-le, meaning ‘that [belongs] to’, and gradually was adopted as a new word in its own right.