Ottomans were successfull because they didnt force the people they conquered, basically the conquered people lived as normal before the Ottomans but they had to swore loyalty to the Sultan. This is one reason why Ottomans were able to conquer many lands.
You are very wrong on that one, the "blood tribute", for one, was nothing "normal".
On the OP question, from what I know it was a matter of many factors, genetics didn't matter (nor religion that much).
It's not that that they were better warriors than either the Europeans , the C. Asians,or the Arabs, but they were better organized, had a flourishing culture that only improved with elements from the neighboring or conquered countrys, and had vast resources of manpower
It also helped that the opposition (at least in Europe) was rarely united