I think you can break down the document into three major ideas very easiliy:
All men are created equal.
Therefore, no men are wise enough to rule over other men without their consent. The way to resolve this paradoxical situation is through liberal democratic instutitions that combine majority rule with the right of the minority to express itself.
The English government (personified as King George III) had shown an unwillingness to extend these rights to American colonists — even though (1) above implies that colonists ought to have no fewer rights than Englishmen.