Europeans had superior technology compared to everyone else.
Here's a radical idea from Yuval's Homo Sapiens book though: The reason the Europeans managed to conquer pretty much everything is the difference in mindset from Europeans and everyone else.
The Ottoman empire and China primarily both had the resources and the know how to be the super powers of our world rather then the Europeans. But where curiosity, glory, and the possibility of wealth drove the Europeans into the unknown, the Chinesse and the Ottomans were content to be in their bubble. Why go discover when everything was already known? The world revolved around China. Anyone outside their borders was a barbarian. Likewise to the Ottomans, they controled the Spice trade, had a pretty nice empire and were content with their position. That need to go explore was an alien concept.
Easy example of this is the landing on the moon by Niel Armstrong. Those people that think it's a hoax, whether it is or not, have one key difference between those who believe that man did land on the moon, the will to imagine. Europeans utilized their minds inventing technology, exploring the world and conquering the known world. They opened their minds to the possibility of what could be rather than what was.
Everyone else was content with living life with closed minds. Why do we need to go to the moon when the moon can't be reached? Why do I need to build a boat and go explore empty ocean? Don't, but those that do might come and re-work your entire shit.
The British colonized China to sell them drugs. Funny what barbarians can do.