<PERSON> suggests that the Articles of Confederation basically failed (which it did). kingledion suggests that differences in manufacturing base and preferred trading partners and attitudes on slavery and loyalty would have kept the colonies apart. Those are both great ideas.
Perhaps another option would be if England did not force the colonies to unite in the first place. The Seven Years War (or more to the point: the "French and Indian War") began when England decided to stop French expansion in the inland areas. <PERSON> had the bright idea that maybe the colonies should create a unified governance for defense of the 13 colonies, thus proposing his Albany Plan and calling for the Albany Congress of 1754 (twenty years before the first Continental Congress).
Maybe, just possibly, if England had decided to wage a Continental war (in Europe) and focus its strong navy and commit troops to attacking France directly (along with its ally <PERSON> of Prussia), the New World could have been spared as a theater of the War. England, knowing that France did not have a navy strong enough to transport troops and supplies to win in America, might have decided that America was theirs for good and that England should therefor focus military action directly against France. 714
This would mean the Colonies would have less to fear, and they might not have felt the need to unite in defense.
Also, maybe England would instead decide to wage economic war against France, and to treat the Colonists a lot better then they actually did. England regarded its colonies as golden gooses that you just squeeze the crap out of. Thus, you get bumbling moves like the Stamp Tax. What if, instead, England had decided that the better way to extract wealth was to invest in growth and productivity, rewarding entrepreneurship and fostering strong market development. As <PERSON> points out, each colony had different things to offer, and under an English crown, these differences would be skillfully exploited for the good of the Crown, but also for the good of each colony individually. If each colony is relatively happy with its relationship to England, then there's nothing to rebel against. Call off the tea party. 145