England's colonization of the New World was due to both "push" and "pull" factors.
Major "push" factors in England included both economic and religious issues. Economically, there were a large number of poor and unemployed people in England in the late 1500s. There was the feeling that England had too many people and something needed to be done with the excess. Religiously, there were Puritans who were unhappy with the government of England and wanted to be able to rule themselves.
In terms of "pull" factors, there were economic and foreign policy factors which were intertwined with one another. England was in a competition with, most importantly, France and Spain for power in Europe. As France and Spain created empires, there was a need for England to follow suit or be left behind. Thus, England began colonization in part to allow it to compete economically, politically, and militarily with the other major powers of Europe.